Pathology Education Instructional Resource - User contributions [en]

Systemic Pathology

2026-10-08T15:15:02Z

Peter Anderson:

HSOM Systemic Pathology Virtual Microscopy Slides
Virtual Microscopy slides for HCOM Systemic Pathology Modules. Slides curated by Dr. Peter Anderson and by Dr. Jennifer Gordetsky (currently at the Department of Pathology, Vanderbilt University).

== [[Alimentary|Alimentary]] ==
== [[Blood-Lymphoid|Blood-Lymphoid]] ==
== [[Bones and Joints|Bones and Joints]] ==
== [[Breast|Breast]] ==
== [[Endocrine|Endocrine]] ==
== [[Genital Urinary-Female|Genital Urinary-Female]] ==
== [[Genital Urinary-Male|Genital Urinary-Male]] ==
== [[Heart and Vascular|Heart and Vascular]] ==
== [[Kidney-Urinary Tract|Kidney-Urinary Tract]] ==
== [[Liver-Biliary|Liver-Biliary]] ==
== [[Muscle & Soft Tissue|Muscle & Soft Tissue]] ==
== [[Nervous System|Nervous System]] ==
== [[Pancreas|Pancreas]] ==
== [[Respiratory System|Respiratory System]] ==
== [[Skin|Skin]] ==
== [[Special Senses|Special Senses]] ==

Special Senses

2026-10-08T15:05:43Z

Peter Anderson: Created page with "=== Special Senses ==="

=== Special Senses ===

Skin

2026-10-08T15:04:44Z

Peter Anderson: Created page with "=== Skin === <gallery heights="250px" widths="250px"> File:IPLab7Melanoma1.jpg|</gallery>"

=== Skin ===
<gallery heights="250px" widths="250px">
File:IPLab7Melanoma1.jpg|</gallery>

Respiratory System

2026-10-08T15:03:25Z

Peter Anderson: Created page with "=== Respiratory System === <gallery heights="250px" widths="250px"> File:IPLab3LobarPneumonia1.jpg|</gallery>"

=== Respiratory System ===
<gallery heights="250px" widths="250px">
File:IPLab3LobarPneumonia1.jpg|</gallery>

Pancreas

2026-10-08T15:01:36Z

Peter Anderson: Created page with "=== Pancreas === <gallery heights="250px" widths="250px"> File:IPLab1FatNecrosis2.jpg|</gallery>"

=== Pancreas ===
<gallery heights="250px" widths="250px">
File:IPLab1FatNecrosis2.jpg|</gallery>

Nervous System

2026-10-08T15:00:02Z

Peter Anderson: Created page with "=== Nervous System ==="

=== Nervous System ===

Muscle & Soft Tissue

2026-10-08T14:59:21Z

Peter Anderson: Created page with "=== Muscle & Soft Tissue ==="

=== Muscle & Soft Tissue ===

Liver-Biliary

2026-10-08T14:58:42Z

Peter Anderson: Created page with "=== Liver-Biliary === <gallery heights="250px" widths="250px"> File:IPLab5Hemochromatosis2b.jpg|</gallery>"

=== Liver-Biliary ===
<gallery heights="250px" widths="250px">
File:IPLab5Hemochromatosis2b.jpg|</gallery>

Kidney-Urinary Tract

2026-10-08T14:58:05Z

Peter Anderson: Created page with "=== Kidney-Urinary Tract === <gallery heights="250px" widths="250px"> File:IPLab2Metaplasia1b.JPG|</gallery>"

=== Kidney-Urinary Tract ===
<gallery heights="250px" widths="250px">
File:IPLab2Metaplasia1b.JPG|</gallery>

Heart and Vascular

2026-10-08T14:57:18Z

Peter Anderson: Created page with "=== Heart and Vascular === <gallery heights="250px" widths="250px"> File:IPLab3HealedMyocardialInfarction1b.jpg|</gallery>"

=== Heart and Vascular ===
<gallery heights="250px" widths="250px">
File:IPLab3HealedMyocardialInfarction1b.jpg|</gallery>

Genital Urinary-Male

2026-10-08T14:55:53Z

Peter Anderson: Created page with "=== Genital Urinary-Male === <gallery heights="250px" widths="250px"> File:IPLab2Atrophy1.jpg|</gallery>"

=== Genital Urinary-Male ===
<gallery heights="250px" widths="250px">
File:IPLab2Atrophy1.jpg|</gallery>

Genital Urinary-Female

2026-10-08T14:55:16Z

Peter Anderson: Created page with "=== Genital Urinary-Female === <gallery heights="250px" widths="250px"> File:IPLab2Hypertrophy6.jpg|</gallery>"

=== Genital Urinary-Female ===
<gallery heights="250px" widths="250px">
File:IPLab2Hypertrophy6.jpg|</gallery>

Endocrine

2026-10-08T14:54:26Z

Peter Anderson: Created page with "=== Endocrine === <gallery heights="250px" widths="250px"> File:IPLab6Hashimoto1.jpg|</gallery>"

=== Endocrine ===
<gallery heights="250px" widths="250px">
File:IPLab6Hashimoto1.jpg|</gallery>

Breast

2026-10-08T14:48:47Z

Peter Anderson: Created page with "=== Breast === <gallery heights="250px" widths="250px"> File:IPLab7IDC1b.jpg|</gallery> * Normal Breast <peir-vm>IPLab7IDC_Normal_Breast</peir-vm> * '''Breast - Benign''' * Fibroadenoma <peir-vm>specialsp/SP-0030</peir-vm> * Fibrcystic Change <peir-vm>UAB-Histology-0000</peir-vm> *Phyllodes Tumor <peir-vm>specialsp/SP-0142</peir-vm> *Myofibroblastoma <peir-vm>specialsp/SP-0159</peir-vm> * '''Breast - Malignant''' * Lobular Carcinoma <peir-vm>specialsp/SP-0036</peir-vm..."

=== Breast ===
<gallery heights="250px" widths="250px">
File:IPLab7IDC1b.jpg|</gallery>
* Normal Breast
<peir-vm>IPLab7IDC_Normal_Breast</peir-vm>

* '''Breast - Benign'''
* Fibroadenoma
<peir-vm>specialsp/SP-0030</peir-vm>
* Fibrcystic Change
<peir-vm>UAB-Histology-0000</peir-vm>
*Phyllodes Tumor
<peir-vm>specialsp/SP-0142</peir-vm>
*Myofibroblastoma
<peir-vm>specialsp/SP-0159</peir-vm>
* '''Breast - Malignant'''
* Lobular Carcinoma
<peir-vm>specialsp/SP-0036</peir-vm>
* Paget Disease and DCIS
<peir-vm>specialsp/SP-0037</peir-vm>
*Invasive Ductal Carcinoma
<peir-vm>specialsp/SP-0038</peir-vm>

Bones and Joints

2026-10-08T14:47:37Z

Peter Anderson: Created page with "=== Bones and Joints === <gallery heights="250px" widths="250px"> File:IPLab7Osteosarcoma5.jpg|</gallery>"

=== Bones and Joints ===
<gallery heights="250px" widths="250px">
File:IPLab7Osteosarcoma5.jpg|</gallery>

Blood-Lymphoid

2026-10-08T14:46:58Z

Peter Anderson: Created page with "=== Blood-Lymphoid === <gallery heights="250px" widths="250px"> File:IPLab5Gaucher1.jpg|</gallery>"

=== Blood-Lymphoid ===
<gallery heights="250px" widths="250px">
File:IPLab5Gaucher1.jpg|</gallery>

Alimentary

2026-10-08T14:46:18Z

Peter Anderson: Created page with "=== Alimentary === <gallery heights="250px" widths="250px"> File:IPLab7ColonCA1.jpg|</gallery>"

=== Alimentary ===
<gallery heights="250px" widths="250px">
File:IPLab7ColonCA1.jpg|</gallery>

CRP-46

2026-10-08T14:37:20Z

Peter Anderson:

'''CRP-46'''
==Clinical History==
Diabetes mellitus with retinopathy, hyperlipidemia, acute renal failure. Gastric bypass 4 months ago. Serum creatinine had increased from 1.8 at the time of surgery to 8.1 two months later. However, the elevated creatinine was not noted at that time and she subsequently took NSAIDs. Two months later her creatinine had risen to 11.

==Gross Description==
Received in transport media are two cores measuring 4 and 12 mm in length and 2 mm in diameter. Four 1-mm pieces are taken for EM. The larger core is bisected and equally divided for immunofluorescence and light microscopy. The remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-046 H&E===
<peir-vm>specialcrp/CRP-046_HE</peir-vm>
===Case CRP-046 PASH===
<peir-vm>specialcrp/CRP-046_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
Sections contain two fragments of renal cortex and one fragment of medulla. A total of thirty glomeruli are examined in the three levels. Twenty-two of these are globally sclerotic, and the remaining glomeruli show marked increase in mesangial matrix with occasional Kimmelstiel-Wilson nodules. There is mild mesangial hypercellularity. The glomerular basement membranes appear diffusely thickened. PASH and trichrome stains show diffuse, moderately severe interstitial fibrosis and tubular atrophy. However, in addition to the chronic tubulointerstitial injury, there is also extensive acute tubular necrosis, and examination of the tissue with polarized light reveals large numbers of oxalate crystals in the tubular epithelium as well as within the tubular lumina. There is patchy mild interstitial inflammation associated with the severe tubular injury. There is severe hyaline arteriolosclerosis.

===Immunofluorescence===
There are three glomeruli in the sections. There is diffuse 3+ linear staining for IgG and albumin along the glomerular basement membranes. There is no glomerular staining for IgM, IgA, C3 or light chains. There is 2+ focal and segmental staining for Clq in the mesangium. There is 3+ linear staining for IgG and albumin along the tubular basement membranes. There is 2+ staining for C3 in the arterioles.

===Electron Microscopy===
Three thick sections are available, but there is only one glomerulus. Ultrastructural examination confirms marked increase in mesangial matrix and diffuse thickening of the glomerular basement membranes. Most of the capillary loops are denuded. No immune complex deposits are identified. The tubular epithelium shows acute degenerative changes, and occasional crystals are noted in tubular epithelial cell cytoplasm as well as within the tubular lumina.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Diabetic nephropathy.

- Oxalosis with severe acute and chronic tubular injury.

This is a very unusual biopsy, which shows two distinct lesions. The first is advanced diabetic nephropathy, with extensive glomerular sclerosis and interstitial fibrosis. However, there is also extensive calcium oxalate deposition, presumably secondary to her gastric bypass five months ago, which has caused severe acute and chronic tubular injury The extent of glomerulosclerosis and tubulointerstitial scarring suggests that significant recovery of renal function is very unlikely.

</spoiler>

CRP-45

2026-10-08T14:37:01Z

Peter Anderson:

'''CRP-45'''
==Clinical History==
Fabry's disease, proteinuria, mild chronic renal insufficiency and hypertension. Ultrasound shows right kidney 9.0 cm and left kidney 11.0 cm. BUN 15, creatinine 1.2, urinary protein 2.8 g/day, creatinine clearance 51 ml/min.

==Gross Description==
Received in transport media are two cores measuring 16 and 6 mm in length and 2 mm in diameter. Representative fragments are submitted for immunofluorescence, electron microscopy and light microscopy.

==Pathology==
===Case CRP-045 H&E===
<peir-vm>specialcrp/CRP-045_HE</peir-vm>
===Case CRP-045 PASH===
<peir-vm>specialcrp/CRP-045_PASH</peir-vm>
===Case CRP-045 Silver===
<peir-vm>specialcrp/CRP-045_Silver</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
Sections contain three fragments of renal cortex, and two of these also contain small portions of renal medulla. There are forty-two glomeruli in the three levels. Twelve are obsolete, although most of these occur in the deepest cortex at the corticomedullary junction. Seven glomeruli show segmental collapse and focal adhesions to Bowman's capsule. However, the most striking change is the generalized enlargement and vacuolization of the glomerular visceral epithelial cells. Similar changes are noted focally in the glomerular mesangium. PASH and trichrome stains show mild focal interstitial fibrosis and tubular atrophy, although there is moderately severe interstitial fibrosis ac the corticomedullary junction around the large vessels. Occasional interstitial foam cells and vacuolated tubular epithelial cells are identified. There is no interstitial inflammation. There is moderately severe arterial and arteriolar sclerosis.

===Immunofluorescence===
There are ten glomeruli in the sections. There is diffuse granular mesangial staining that is graded 2+ for IgM and IgA, although the IgA staining is definitely slightly less intense than the IgM staining. There is focal and segmental trace mesangial staining for kappa and lambda. There is l+ focal and segmental staining for C3 and Clq. There is no glomerular staining for IgG or albumin. Tubular epithelium contains numerous protein droplets that stain for IgA, C3, albumin and light chains. There is no staining of the tubular basement membranes. There is 4+ staining for C3 in the vessel walls.

===Electron Microscopy===
Four thick sections containing a total of four glomeruli are available. One shows segmental collapse. By light microscopy, numerous inclusions are easily visible in the visceral epithelial cells. Ultrastructural examination confirms the presence of numerous lamellated lipid inclusions ("myeloid bodies") in the visceral epithelium, as well as a few inclusions in mesangial, endothelial and parietal epithelial cells. Occasional inclusions are also noted in tubular epithelium and vascular myocytes. The capillary basement membranes are not significantly thickened, but there is diffuse fusion of the foot processes. Some capillary loops are occluded by long curved structures that have been called membranous convoluted structures. These structures have been described in many disease and even in normal glomeruli. They are thought to arise from focal lysis of cellular elements that are part of the membrane material, and they appear to have no clinical significance. No immune complex deposits are identified.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Fabry's disease.

These light and electron microscopic features are typical of Fabry's disease. The segmental glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arterial and arteriolar sclerosis are typically seen in the latter stages of this disease. There is no evidence for a superimposed immune complex-mediated glomerulopathy. Overall, tubulointerstitial scarring is relatively mild.

</spoiler>

CRP-44

2026-10-08T14:36:45Z

Peter Anderson:

'''CRP-44'''
==Clinical History==
History of polymyositis, hypercalcemia and proteinuria. Negative serology.

==Gross Description==
Received in transport medium are two cores that measure 12 and 18 mm in length and 2 mm in diameter. A 5-mm fragment is taken for immunofluorescence, four 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-044 H&E===
<peir-vm>specialcrp/CRP-044_HE</peir-vm>
===Case CRP-044 PASH===
<peir-vm>specialcrp/CRP-044_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of two fragments of renal cortex that contain eight-six glomeruli in the three levels. Fourteen of these are obsolete, but the rest show minimal mesangial expansion and no proliferation. The capillary basement membranes are unremarkable with the silver stain. The PASH and trichrome stains show diffuse mild interstitial fibrosis and focal tubular atrophy.
There are numerous lymphoid aggregates throughout the cortex, and there are also numerous noncaseating granulomata. Special stains for acid fast bacilli and fungi are negative with adequate controls. Occasional examples of mild tubulitis are identified. There is mild hyaline arteriosclerosis. The larger vessels are unremarkable.

===Immunofluorescence===
There are five glomeruli in the sections. There is 1+ segmental mesangial staining for IgM, IgA, C3 and lambda. There is no glomerular staining for IgG, Clq, albumin or kappa. There is no staining of the tubular basement membranes or vessels.

===Electron Microscopy===
Three thick sections are available, but there is only one glomerulus, which is unremarkable by light microscopy. Ultrastructural examination reveals no significant increase in mesangial matrix, and no mesangial deposits are identified. The glomerular basement membranes show focal mild thickening and wrinkling, and there is also focal fusion of the foot processes. No deposits are noted along the capillary loops.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Granulomatous interstitial nephritis, consistent with sarcoidosis.

These features are most consistent with granulomatous interstitial nephritis. The differential diagnosis includes sarcoidosis and an allergic drug-induced reaction, but the clinical history is much more suggestive of sarcoidosis. There is only mild tubulointerstitial scarring, suggesting that significant recovery of renal function is possible with resolution of the acute interstitial inflammation.

</spoiler>

CRP-42

2026-10-08T14:36:07Z

Peter Anderson:

'''CRP-42'''
==Clinical History==
Thirteen-year-old black female with sickle cell disease, systemic lupus erythematosus and proteinuria. Percutaneous needle biopsy of the right kidney was performed.

==Gross Description==
The specimen is labeled “Renal bx”. It consists of two portions of light tan tissue measuring 0 8 x 0.1 x 0.1 cm and 0.3 x 0.1 x 0.1 cm. (Jar 0)

==Pathology==
===Case CRP-042 H&E===
<peir-vm>specialcrp/CRP-042_HE</peir-vm>
===Case CRP-042 PASH===
<peir-vm>specialcrp/CRP-042_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The sections show portions of sub capsular cortex. Up to twelve glomeruli are available for examination on multiple sections. The glomeruli are enlarged and show mild segmental expansion of the mesangial matrix and segmental thickening of the peripheral capillary walls, which have a beaded appearance on trichrome and Jones silver stains. Numerous capillary loops are ectatic and contain sickled erythrocytes. No globally or segmentally sclerosed glomeruli are found. The interstitium, tubules and blood vessels are essentially unremarkable. One tubulointerstitial calcific deposit is noted. There are no detectable glomerular or tubular hemosiderin deposits. ABPASH, trichrome and Jones silver stains have appropriately reactive controls.

===Immunofluorescence===
One glomerulus is available for examination by immunofluorescence on sections stained with IgG, IgM, IgA, C1q and C3. There is finely granular basement membrane staining with IgM (1+) and linearly granular staining with IgA (trace). No glomerular staining is noted with IgG, C1q and C3. No glomeruli are available for examination on sections stained with C4, fibrinogen, albumin or kappa and lambda light chains.

===Electron Microscopy===
Three glomeruli are present on multiple plastic-embedded BFMB-stained sections. The glomeruli are enlarged and show segmental mesangial matrix expansion and segmental thickening of the capillary walls. The capillary lumina contain sickled erythrocytes. Ultrastructural examination shows segmental thinning and segmental wrinkling of the glomerular basement membranes. There is extensive mesangial interposition and segmental accumulation of subendothelial flocculent material. The capillary lumina are ectatic and contain sickled erythrocytes. The mesangium is expanded by basement membrane-like material. There is segmental foot process obliteration of the visceral epithelial cells. Some of the visceral epithelial cells contain irregular electron dense iron deposits and ingested effete erythrocytes. No electron-dense deposits are recognized.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, right, biopsy:
Sickle Cell Nephropathy

The biopsy shows light microscopy, immunofluorescence and ultrastructural features of the nephropathy of sickle cell disease. Features of systemic lupus erythematosus are not recognized.

</spoiler>

CRP-41

2026-10-08T14:35:52Z

Peter Anderson:

'''CRP-41'''
==Clinical History==
The patient is a 53 year old male who has had diabetes for many years. He also has multiple myeloma with associated renal insufficiency and anemia.

==Gross Description==
Received in Zeus fixative are two cores that each measure 12 mm in length and 1 mm in diameter. These are entirely submitted for immunofluorescence. Received in Carson's fixative are two cores each measuring 16 mm in length and l mm in diameter. Three 1-mm pieces are taken for EM and the remainder is submitted for light microscopy.

==Pathology==
===Case CRP-041 H&E===
<peir-vm>specialcrp/CRP-041_HE</peir-vm>
===Case CRP-041 PASH===
<peir-vm>specialcrp/CRP-041_PASH</peir-vm>
===Case CRP-041 Trichrome===
<peir-vm>specialcrp/CRP-041_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of two long fragments of renal cortex with small portions of medulla. There are sixty-six glomeruli in the three levels. Thirty-one of these are obsolete, and many of the remaining glomeruli show segmental sclerosis and focal hyalinosis. All of the glomeruli show nodular and diffuse intracapillary sclerosis, and several distinct Kimmelstiel-Wilson nodules are identified. The capillary basement membranes are generally quite thick with the PASH and silver stains, although no spike formation or splitting are identified. There is severe diffuse interstitial fibrosis with corresponding tubular atrophy. The tubules generally show markedly thickened basement membranes, which arc also split and generally wrinkled. There are occasional mononuclear inflammatory cells throughout the fibrotic interstitium, but there is no tubulitis. There are no casts with the characteristic appearance of light chain casts. The arterioles and small arteries show moderate intimal thickening, but the vascular injury is less than one might expect for this degree of glomerulosclerosis and interstitial fibrosis. A Congo red stain is negative in the glomeruli and vessels with an adequate positive control.

===Immunofluorescence===
There are fifteen glomeruli in the sections. There is 2+ focal and segmental mesangial staining for IgM, C1q and C3. There is no glomerular staining for IgG, IgA or light chains. Tubular basement membranes show 2+ linear staining for IgG and albumin. There is no staining for kappa or lambda light chain in the tubular basement membranes. There is no staining of the vessels.

===Electron Microscopy===
Three thick sections containing a total of two glomeruli are available. These are similar and show diffuse intercapillary glomerular sclerosis and global atrophy. Tubular basement membranes show marked thickening as described above. Ultrastructural examination reveals diffuse uniform thickening of the capillary basement membranes. These basement membranes are generally about three to four times the normal thickness. There is diffuse fusion of the epithelial cell foot processes. Mesangial matrix is markedly increased. However, no immune complexes deposits or fibrillary deposits are identified in the glomeruli or tubular basement membranes.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Diabetic nephropathy, severe.

These findings are most consistent with advanced diabetic nephropathy. Since the patient has a history of multiple myeloma, the biopsy was carefully examined for amyloidosis or some other type of light chain related disease. However, there is no evidence in this biopsy for amyloidosis, light chain cast nephropathy or light chain deposition disease. The marked degree of glomerulosclerosis and interstitial scarring is consistent with an extremely poor prognosis for this kidney.

</spoiler>

CRP-40

2026-10-08T14:35:29Z

Peter Anderson:

'''CRP-40'''
==Clinical History==
The patient is a 55-year-old African American man with HIV, history of hypertension and chronic renal insufficiency. Further decrease in renal function (creatinine 6.4; 2.7 3 days previously).

==Gross Description==
Received in Carson's fixative are two needle cores that measure 10.0 and 11.0 mm in length and 1.0 mm in diameter. Four 1.0 mm pieces are separated for ultrastructural studies and the remainder is processed for light microscopy. An additional core measuring 12.0 x 1.0 mm is received in Zeuss fixative and is processed for immunofluorescence microscopy.

==Pathology==
===Case CRP-040 H&E===
<peir-vm>specialcrp/CRP-040_HE</peir-vm>
===Case CRP-040 PASH===
<peir-vm>specialcrp/CRP-040_PASH</peir-vm>
===Case CRP-040 Silver===
<peir-vm>specialcrp/CRP-040_Silver</peir-vm>
===Case CRP-040 Trichrome===
<peir-vm>specialcrp/CRP-040_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
Sections are of four needle core pieces of renal cortex. Two of these include segments of the renal capsule and the largest piece contains a sample of the superficial medulla. There are fifty-nine glomeruli counted, thirty-eight of which obsolete. The viable glomeruli show variable mesangial matrix increase and segmental sclerosing and hyalinosing lesions in nine of the twenty-one viable glomeruli. Several of these lesions show features of lobular collapse, some with modest visceral epithelial cell hypertrophy. There are no necrotizing lesions nor crescents. The tublulointerstitium shows significant interstitial widening with wide spread chronic inflammation. There is severe tubular atrophy, commensurate with the degree of glomerulosclerosis. Multiple examples of microcystic dilatation of lobules are noted. The vasculature is well sampled and shows moderate to severe concentric thickening of the small arteries (inter and intralobular), suggestive of chronic hypertensive injury, as well as moderate segmental thickening of arterioles. There are no thrombotic or vasculitic lesions.

===Immunofluorescence===
Twelve glomeruli are available for study, six of which are obsolete. Viable glomeruli show local and segmental coarse granular staining of the mesangium for IgM (1-2+), C3 (3+), C1q (2+), and kappa light chain (2+). IgG, IgA, albumen and lambda light chains are negative. There is no significant staining of the tubulointerstium or vasculature.

===Electron Microscopy===
Six glomeruli are present in the four tissue pieces processed for EM, five of which are globally sclerosed. A single viable glomerulus is studied ultrastructurally, and shows variable mesangial matrix increase, irregular thickening and collapse of the glomerular basement membranes and prominent, widespread effacement of the visceral epithelium. There are scattered hyaline-type protein deposits, but no immune complex deposits are identified.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, left, needle biopsy:
• HIV nephropathy with advanced nephrosclerosis.
• Hypertensive vasculopathy, moderate.

The biopsy shows classic features of advanced HIV nephropathy. This is superimposed on significant hypertensive vasculopathy. No evidence of an immune complex glomerulonephritis is found.

</spoiler>

CRP-39

2026-10-08T14:35:13Z

Peter Anderson:

'''CRP-39'''
==Clinical History==
The patient is a 54 year old white woman. Hematuria, BUN 11, creatinine 0.6, urinary protein 131 mg/24 hours. BP 130/70.

==Gross Description==
Received in transport media are two cores of renal tissue measuring 16.5 and 5.5 mm in length and 2 mm in diameter. A 1-mm fragment is taken from the 5.5 mm piece for EM, and the remaining portion is submitted for immunofluorescence. The entire 16 mm fragment is submitted for light microscopy.

==Pathology==
===Case CRP-039 H&E===
<peir-vm>specialcrp/CRP-039_HE</peir-vm>
===Case CRP-039 PASH===
<peir-vm>specialcrp/CRP-039_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a large fragment of renal cortex and medulla. The middle of the specimen is medulla, and there are small portions of cortex on each end. There are approximately fifty-three glomeruli in the sections. Two are obsolete, and another shows advanced ischemic thickening and collapse. However, the remaining glomeruli are all similar and show minimal focal mesangial expansion with no significant hypercellularity. There are no segmental areas of proliferation or sclerosis. No crescents are present. The silver stain does not demonstrate any abnormalities of the basement membranes. Some of the glomeruli contain red blood cells in Bowman’s space indicating hematuria of glomerular origin. There is a definite diffuse mild increase in interstitial fibrous tissue. No inflammatory infiltrates are present. There is no significant tubular atrophy or dropout. Large vessels show mild focal intimal fibrosis but are otherwise unremarkable. The arterioles are also unremarkable.

===Immunofluorescence===
There are eight glomeruli in the sections. All of these show normal morphology. There is trace mesangial staining for IgM, but all other stains in the glomeruli are negative. There is no staining of the tubules or vessels.

===Electron Microscopy===
One thick section containing three glomeruli is available. These show essentially normal morphology by light microscopy. Ultrastructural examination reveals capillary basement membranes with rather diffuse thinning of the lamina densa. The average thickness of the basement membrane is approximately 190 nm (range 170-210 nm), which is about one-half of the normal thickness for adult glomerular basement membranes. There is no significant effacement of the epithelial foot processes. No electron dense deposits are identified along the capillary basement membranes or in mesangial regions.

</div></div>

<spoiler text="Diagnosis and Comments">
basement membrane is approximately 190 nm (range 170-210 nm), which is about one-half of the normal thickness for adult glomerular basement membranes. There is no significant effacement of the epithelial foot processes. No electron dense deposits are identified along the capillary basement membranes or in mesangial regions.

Diagnosis:
Kidney, needle biopsy – This basement membrane nephropathy.
- Mild arteriosclerosis

These biopsy findings are most consistent with thin basement membrane nephropathy. There is no evidence for immune-complex mediated glomerulopathy such as IgA nephropathy. This ultrastructural appearance can also be seen in Alport’s syndrome (hereditary nephritis), and in women it may be the only ultrastructural finding. However, the normal light microscopic appearance is more consistent with thin basement membrane nephropathy.

</spoiler>

CRP-38

2026-10-08T14:34:48Z

Peter Anderson:

'''CRP-38'''
==Clinical History==
The patient is a 34 year old female with positive family history of chronic renal failure. Urinary protein 500 mg per 24 hours, BUN 10, creatinine 0.9. Rule out familial nephropathy.

==Pathology==
===Case CRP-038 H&E===
<peir-vm>specialcrp/CRP-038_HE</peir-vm>
===Case CRP-038 PASH===
<peir-vm>specialcrp/CRP-038_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of two fragments of cortex, one of which contains the corticomedullary junction and a small portion of medulla. There are at least twelve glomeruli in the biopsy. One is obsolete. The remaining glomeruli are all similar and show mild local increase in mesangial matrix without mesangial cell proliferation. Capillary basement membranes are remarkable with the special stains and the peripheral capillary loops are patent. There are no areas of segmental sclerosis. There is minimal interstitial fibrosis, and the tubules are generally well preserved. No interstitial foam cells are identified. The vessels are essentially unremarkable. No inflammatory infiltrates are present.

===Immunofluorescence===
There are two glomeruli in the sections. There is focal and segmental 1+ staining for C3 in the mesangium. Stains for IgG, IgM, IgA, C1q, fibrinogen and light chains are negative in the glomeruli. Occasional tubules contain albumin droplets in the epithelium. There is no staining of the vessels.

===Electron Microscopy===
One thick section containing four glomeruli is present. All of these are similar and show the same characteristics noted in light microscopy. Ultrastructural examination shows variable thickening, thinning and lamellation of the glomerular basement membrane. The thick segments measure up to 800 nm, while the thin segments measure as little as 130 nm. The lamina densa has focal areas of clear electron-lucent areas, which sometimes contain round electron-dense granules. The altered capillary walls show epithelial foot process obliteration. No electron dense deposits are identified in capillary basement membranes or mesangial regions.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy – Alport Syndrome (Hereditary nephritis)

These findings are most consistent with hereditary nephritis. The most characteristic ultrastructural feature in this disease is the variable thickening, thinning, and lamellation of the glomerular basement membranes. However, in females there may simply be diffusely attenuated segments of glomerular basement membranes. This finding may also be present in thin basement membrane nephropathy. However, the additional presence of focal lamellation of basement membranes in this case, as well as the history of relatives with chronic renal insufficiency, is more consistent with hereditary nephritis.

Females tend to have a milder clinical course, and the good preservation of the tubules and the interstitium in this case suggests that this patient has a relatively good prognosis.

</spoiler>

CRP-37

2026-10-08T14:34:31Z

Peter Anderson:

'''CRP-37'''
==Clinical History==
The patient is a 60 year old black male. Cadaveric renal transplant three months ago. Original disease was membranous glomerulonephritis. Biopsy one month ago showed Banff I-B acute rejection. Baseline creatinine was 1.8. Following treatment for rejection creatinine decreased from 3.3 to 2.4, but it never returned to baseline.

==Gross Description==
Received in transport media is one core measuring 14 x 1 mm, which is entirely submitted for light microscopy.

==Pathology==
===Case CRP-037 H&E===
<peir-vm>specialcrp/CRP-037_HE</peir-vm>
===Case CRP-037 PASH===
<peir-vm>specialcrp/CRP-037_PASH</peir-vm>
===Case CRP-037 IHC BK polyomavirus===
<peir-vm>specialcrp/CRP-037_IHC-BK_polyomavirus</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
Sections contain one fragment of mostly renal medulla with small portions of cortex. There are only four glomeruli in the three levels. All of these are unremarkable. There is patchy interstitial inflammation and numerous examples of tubulitis are identified. The most severely involved tubules contain seven to eight lymphocytes in cross section. There is interstitial edema, and trichrome stain shows mild focal interstitial fibrosis. However, most of the striking change in this biopsy is in the tubular epithelium. A number of the epithelial cells are swollen and contain enlarged nuclei. Occasional intranuclear inclusions are identified, and a few tubular epithelial cells also contain cytoplasmic granules. Occasional mitoses are noted in the epithelium. An immunohistochemical stain for BK polyomavirus is positive in the tubular epithelium, and the control is adequate. Stains for CMV, Epstein-Barr virus, herpes simplex, and adenovirus are negative with adequate controls. Only a few arterioles are present in the sample, and they are unremarkable.

===Electron Microscopy===
Following examination of the tissue submitted for light microscopy, the remaining tissue was removed from the paraffin block and reprocessed for electron microscopy. This yielded four thick sections with four glomeruli, but two of these are obsolete. Tubular epithelial cells with enlarged atypical nuclei are noted in several of the thick sections. Ultrastructural examination reveals occasional degenerated tubular epithelial cells with clear nuclei, but no definitive viral particles are identified.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, allograft, needle biopsy – Moderate acute interstitial rejection, Banff grade 1-A.
- BK polyomavirus infection.

These features are most consistent with two distinct lesions. There is still significant acute interstitial rejection, although comparison with the previous biopsy shows definitely less severe rejection than was present one week ago. However, in addition to the acute intestinal rejection there is BK polyomavirus infection. After identification of BK virus in this biopsy, the previous biopsy was stained for BK virus and rare positive tubular epithelial cells were noted.

</spoiler>

CRP-36

2026-10-08T14:34:14Z

Peter Anderson:

'''CRP-36'''
==Clinical History==
Cadaveric renal transplant three months ago. Primary renal disease was polycystic kidney disease. History of CMV infection. BUN 50, creatinine 1.9.

==Gross Description==
Received in transport media is one core measuring 8 x 1 mm. The entire specimen is submitted for light microscopy.

==Pathology==
===Case CRP-036 H&E===
<peir-vm>specialcrp/CRP-036_HE</peir-vm>
===Case CRP-036 PASH===
<peir-vm>specialcrp/CRP-036_PASH</peir-vm>
===Case CRP-036 Silver===
<peir-vm>specialcrp/CRP-036_Silver</peir-vm>
===Case CRP-036 IHC-CMV===
<peir-vm>specialcrp/CRP-036_IHC-CMV</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a fragment of renal cortex that contains thirty-three glomeruli in the three levels. None of these are obsolete, and none show segmental sclerosis. Most of the glomeruli show a striking pattern of glomerular injury. The principle features are diffuse endothelial cell hypertrophy and necrosis, infiltration by mononuclear cells, and mesangiolysis. The PASH stain shows peculiar webs of PAS· positive material in the capillary lumina. Most of the glomerular capillary lumina are obliterated. No viral inclusions axe identified in any of these cells. In addition to the glomerular injury, there it also severe acute interstitial rejection. There is diffuse interstitial edema, and numerous examples of emperipolesis are noted. The most severely involved tubules contain more than ten lymphocytes in cross-section. There is minimal interstitial fibrosis, and there is no significant tubular atrophy. Only a few small vessels and arterioles area present. None of these show evidence of vascular rejection. Immunohistochemical staining for cytomegalovirus (CMV) is positive in five glomeruli. The staining is confined to endothelial cells. There is no staining in the tubular epithelium. The positive and negative controls are adequate.

===Electron Microscopy===
Following examination of the tissue submitted for light microscopy, a portion of the remaining issue was removed from the paraffin block and submitted for electron microscopy. This yielded three thick sections with a total of three glomeruli. One of these is obsolete, but the other two are relatively well preserved. Unfortunately neither contains the swollen endothelial cells noted by light microscopy. There is minimal increase in mesangial matrix, and the glomerular basement membranes are unremarkable. The foot processes are intact. No viral particles are identified in the glomerular endothelial cells.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, allograft, needle biopsy·- Moderately severe acute interstitial rejection, Banff grade I-B.
- Acute allograft glomerulopathy (CMV glomerulopathy).

These histologic features are most consistent with two distinct lesions. There is severe acute interstitial rejection, and the degree of tubulitis corresponds to Banff grade I-B. However, there is also a very unusual glomerular lesion that has been described in the literature as “acute allograft glomerulopathy”. This is a distinctive glomerular injury in renal allografts that has been associated with CMV viremia, although similar changes have occasionally been described in the absence of CMV infection. Interestingly, the published cases almost never show evidence of CMV in the glomerular cells. Typically in the published cases no viral particles are detectable by electron microscopy, and no viral antigens are detected. In contrast, this biopsy shows definite immunohistochemical staining for CMV. However, electron microscopic examination failed to identify viral particles.

</spoiler>

CRP-35

2026-10-08T14:33:59Z

Peter Anderson:

'''CRP-35'''
==Clinical History==
The patient is a 25 year old female who is status post renal transplant two years ago. She presents for explant nephrectomy due to rejection.

==Gross Description==
The specimen is received in a container labeled with the patient's name, medical record number and “transplant nephrectomy”. Received in saline solution is a fragmented and distorted nephrectomy specimen that weighs in aggregate 250 grams and measures 15 x 8 x 4 cm in greatest dimension. The kidney is externally covered by a tan-pink shiny capsule with areas of petechial hemorrhages. This capsule strips with ease, revealing a red-brown granular external surface. The cut surface is pale tan with congestion. The cortico-medullary junction cannot be grossly identified and the portion of pelvico-calyceal system that can be grossly identified, is lined by a tan-white smooth glistening and congested mucosa. No gross lesions are present. The specimen is submitted in four cassettes.

==Pathology==
===Case CRP-035 H&E===
<peir-vm>specialcrp/CRP-035_HE</peir-vm>
===Case CRP-035 PASH===
<peir-vm>specialcrp/CRP-035_PASH</peir-vm>
===Case CRP-035 IHC===
<peir-vm>specialcrp/CRP-035_IHC</peir-vm>
===Case CRP-035 IHC_control===
<peir-vm>specialcrp/CRP-035_IHC_control</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
A1-A4 – Sections through transplant kidney. A microscopic examination has been performed.

===Immunofluorescence===
IHC-CD68

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, transplant nephrectomy – Malakoplakia
- Moderately severe chronic vascular rejection and acute vascular rejection
- Acute tubulitis.
- Tubular atrophy and interstitial fibrosis

Much of the renal parenchyma is replaced by sheets of large eosinophilic macrophages with occasional small round structures in their cytoplasm, consistent with Michaelis-Guttman bodies. These macrophages stain strongly with CD68 and are negative for cytokeratin. The stains for fungal organisms, acid fast bacilli and Whipples bacteria are negative.

</spoiler>

CRP-34

2026-10-08T14:33:41Z

Peter Anderson:

'''CRP-34'''
==Clinical History==
The patient is a 23 year old male with history of end-stage renal disease secondary to IgA nephropathy. Status post living related donor transplant. Creatinine has increased from 1.8 to 3.0. Hematuria, but no proteinuria.

==Gross Description==
Received in transport media are two cores measuring 16 mm and 15 mm in length and 0.5 mm in diameter. Two 1-mm pieces are taken for EM, a 15-mm piece is submitted for immunofluorescence, and the remainder is submitted for light microscopy.

==Pathology==
===Case CRP-034 H&E===
<peir-vm>specialcrp/CRP-034_HE</peir-vm>
===Case CRP-034 PASH===
<peir-vm>specialcrp/CRP-034_PASH</peir-vm>
===Case CRP-034 Silver===
<peir-vm>specialcrp/CRP-034_Silver</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of two fragments of renal cortex, one of which has a small piece of capsule on one end. The other fragment has a very tiny portion of medulla on one end. There are sixteen glomeruli in the three levels. None of these are obsolete, and none show segmental sclerosis. There is focal mild increase in mesangial matrix, but there is no hypercellularity. The capillary basement membranes are unremarkable with the silver and PASH stains. There is mild focal fibrosis with corresponding focal tubular atrophy. There is also interstitial edema, and a number of mononuclear inflammatory cells are present throughout the cortex. These are primarily lymphocytes with occasional eosinophils. Tubulitis is easily identified, although the most severely involved tubules contain less than ten lymphocytes per cross-section. Arterioles show mild thickening, but there is no arteritis

===Immunofluorescence===
There are four glomeruli in the sections. There is 1+ granular mesangial staining for IgM, but there is no glomerular staining for IgG, IgA, Clq, C3 or light chains. Blood vessels show 1+ staining for C3, and there is also focal staining for C3 in tubular epithelial cells. There is no staining of the tubular basement membranes.

===Electron Microscopy===
Two thick section are available, and each contains one glomerulus. These are similar to those described above and show essentially normal morphology. Ultrastructural examination reveals mild thickening of the capillary basement membranes, and there is focal fusion of the epithelial foot processes. No electron dense deposits are identified in the glomeruli.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, transplant, needle. biopsy - Mild acute interstitial rejection, Banff Grade I.

</spoiler>

CRP-33

2026-10-08T14:33:20Z

Peter Anderson:

'''CRP-33'''
==Clinical History==
Status post cadaveric transplant 15 months ago. Creatinine 3.0.

==Gross Description==
Received in transport media is one core measuring 10 mm in length and 0.5 mm in diameter. It is entirely submitted for light microscopy.

==Pathology==
===Case CRP-033 H&E===
<peir-vm>specialcrp/CRP-033_HE</peir-vm>
===Case CRP-033 PASH===
<peir-vm>specialcrp/CRP-033_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a fragment of renal cortex with a small portion of capsule on one end. There are sixteen glomeruli in the three levels examined. Three of these area obsolete, but the remainder are similar and show essentially normal morphology. There is mild patchy interstitial fibrosis with corresponding focal mild tubular atrophy. Occasional small collections of lymphocytes are present in the more fibrotic areas, and examples of mild tubulitis are identified in all three levels. However, the degree of tubulitis is relatively mild, with only two or three lymphocytes generally identified per tubular cross-section. The arterioles and small arteries show minimal intimal thickening, but they are otherwise unremarkable.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, transplant, needle biopsy·- Very mild acute interstitial rejection (Banff borderline).

These findings are most consistent with mild acute interstitial rejection. Overall, the tubulointerstitial preservation is quite good, and there are no significant pathologic changes in the glomeruli or vessels.

</spoiler>

CRP-32

2026-10-08T14:33:03Z

Peter Anderson:

'''CRP-32'''
==Clinical History==
The patient is a 25 year old black female. Status post cadaveric renal transplant three weeks ago Acute rejection by scan. Open biopsy showed apparently viable kidney. Patient has been treated with ATGAM. BUN 80, creatinine 8.5.

==Gross Description==
Received in transport media is one wedge-shaped fragment of tissue measuring 5 x 3 x 2 mm in greatest dimensions. It is entirely submitted for light microscopy.

==Pathology==
===Case CRP-032 H&E===
<peir-vm>specialcrp/CRP-032_HE</peir-vm>
===Case CRP-032 PASH===
<peir-vm>specialcrp/CRP-032_PASH</peir-vm>
===Case CRP-032 PASH recut===
<peir-vm>specialcrp/CRP-032_PASH_recut</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a fragment of superficial renal cortex with 44 glomeruli in the three levels. These show minimal mesangial expansion, but they are otherwise unremarkable. There is diffuse marked interstitial edema, and there is focal mild tubular atrophy. There is mild focal interstitial fibrosis immediately beneath the renal capsule. There is a diffuse heavy mononuclear cell infiltrate throughout the biopsy, and numerous examples of tubulitis are identified. The most severely involved tubules contain 8 to 9 lymphocytes per cross section. There is no significant tubular dilatation or epithelial simplification to suggest acute tubular necrosis. Relatively few arterioles and small arteries are identified in the biopsy. There is focal endothelial cell swelling, but the vessels are otherwise unremarkable.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, transplant, needle biopsy – Moderately severe acute interstitial rejection. (Banff grade II).

</spoiler>

CRP-31

2026-10-08T14:32:40Z

Peter Anderson:

'''CRP-31'''
==Clinical History==
The patient is a 36 year old black male with chronic rejection.

==Gross Description==
Received in saline is one wedge shaped fragment of cortex measuring 5 x 3 x 2 mm in greatest dimensions. This is bisected, and one-half is submitted for light microscopy. Note that the surgical pathology request sheet states that this is a transplant nephrectomy, but the only specimen received is this wedge shaped fragment.==Pathology==
===Case CRP-031 H&E===
<peir-vm>specialcrp/CRP-031_HE</peir-vm>
===Case CRP-031 PASH===
<peir-vm>specialcrp/CRP-031_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a large fragment of renal cortex that contains 60 to 70 glomeruli per level. About 10% of these are obsolete. The remaining glomeruli are generally hypercellular, although the cellularity appears to be inflammatory cells distending the capillary loops rather than mesangial or endothelial cell proliferation. The PASH stain shows thickened basement membrane and focal splitting. Some of the glomeruli are severely atrophic with markedly thickened and wrinkled basement membranes. A few of the glomeruli are globally necrotic. There is diffuse marked interstitial fibrosis with marked tubular atrophy. There are also a number of large collections of mononuclear inflammatory cells throughout the biopsy and numerous examples of tubulitis are identified. The most severely involved tubules contain six to eight lymphocytes per tubular cross section. There are patchy interstitial hemorrhages throughout the biopsy. The vessels generally show obliterative endarteritis, although a few still have a small lumen. Several of the vessels also demonstrate intimal arteritis. Focal necrosis is noted in some of the vessel walls.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, wedge biopsy - Severe acute interstitial and vascular rejection, Banff grade III.
- Severe chronic rejection.

These findings are most consistent with severe acute and chronic rejection. This degree of acute interstitial and vascular rejection corresponds to grade III in the Banff classification.

</spoiler>

CRP-30

2026-10-08T14:32:06Z

Peter Anderson:

'''CRP-30'''
==Clinical History==
The patient is a 42 year old male who is status post double lung transplant two years ago for alpha-1-antitrypsin deficiency. The patient has nephrotic range proteinuria. BUN 44, creatinine 2.3, creatinine clearance 65 ml/min, urinary protein 6.5 g/24 hr. BP 144/90.

==Gross Description==
Received in transport media is one core measuring l.5 cm in length and 2 mm in diameter. Two l mm pieces are taken for EM, a 4 mm piece is taken for immunofluorescence, and the remaining tissue is processed for light microscopy.

==Pathology==
===Case CRP-030 H&E===
<peir-vm>specialcrp/CRP-030_HE</peir-vm>
===Case CRP-030 PASH===
<peir-vm>specialcrp/CRP-030_PASH</peir-vm>
===Case CRP-030 Silver===
<peir-vm>specialcrp/CRP-030_Silver</peir-vm>
===Case CRP-030 Trichrome===
<peir-vm>specialcrp/CRP-030_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a fragment of renal cortex that contains at least 12 glomeruli. Five of these are obsolete. The remaining glomeruli show a range of morphology. Some of them show essentially normal morphology, but most show varying degrees of mesangial sclerosis with a few exhibiting segmental sclerosis and complete collapse of the capillary tufts. A few of the glomeruli also demonstrate prominent congestion. There is no glomerular necrosis, and no thrombi are identified in any of the glomeruli. Mesangial cellularity is only mildly increased. There is diffuse moderate interstitial fibrosis with corresponding tubular atrophy. Many of the remaining tubules demonstrate dilation, epithelial simplification and focal epithelial cell necrosis. Occasional lymphocytes and plasma cells are scattered throughout the interstitium, but there is no tubulitis. The most striking change in the biopsy is in the arterioles and small arteries. The arterioles uniformly show marked hyalinosis with almost complete obliteration of the lumina. The small arteries show moderate intimal mucoid thickening. Several of the arterioles also contain fibrin thrombi. None of the vessels demonstrate vasculitis.

===Immunofluorescence===
There are eighteen glomeruli in the sections. Three of these are obsolete. There is trace mesangial staining for IgM diffusely, and there is 2+ focal and segmental mesangial staining for IgM, IgA, C3 and light chains. Blood vessels show 2+ irregular staining for C3.

===Electron Microscopy===
Two thick sections containing a total of eleven glomeruli are available. One of these is obsolete, but the rest show essentially normal morphology by light microscopy. Ultrastructural examination reveals mild thickening of the glomerular basement membranes, and there is only focal fusion of the visceral cell foot processes. Mesangial regions are slightly expanded by matrix but there is no significant mesangial cell proliferation. No electron dense deposits are identified in the glomeruli. The tubules show atrophy and focal epithelial cell necrosis.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Marked hyaline arteriolosclerosis and focal arteriolar thrombosis, consistent with cyclosporine-associated arteriopathy.

These findings are most consistent with cyclosporine arteriopathy. The vascular lesions are quite characteristic. However, similar histology may also be seen in thrombotic microangiopathy, which should be ruled out clinically. The sever degree of vascular injury portends a very poor prognosis for this kidney.

</spoiler>

CRP-29

2026-10-08T14:31:50Z

Peter Anderson:

'''CRP-29'''
==Clinical History==
The patient is a 24 year old black male. History of lupus with recent sharp decline in renal function. BUN 54, creatinine 5.9, albumin 2.3. Urinalysis shows moderate blood and >300 mg/dl.

==Gross Description==
Received in Zeus fixative are three cores measuring 3, 8 and 15 mm in length and 1 mm in diameter, which are entirely submitted for immunofluorescence. Received in Carson's fixative are three cores measuring 9, 12 and 18 mm in length. Three 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-029 H&E===
<peir-vm>specialcrp/CRP-029_HE</peir-vm>
===Case CRP-029 PASH===
<peir-vm>specialcrp/CRP-029_PASH</peir-vm>
===Case CRP-029 Silver===
<peir-vm>specialcrp/CRP-029_Silver</peir-vm>
===Case CRP-029 Trichrome===
<peir-vm>specialcrp/CRP-029_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
Sections contain five cores of renal cortex with at least forty-five glomeruli. Three are globally sclerotic, but there are no segmental sclerotic lesions. The glomeruli show moderately increased mesangial matrix with mesangial and endocapillary proliferation. Ten glomeruli contain cellular crescents. About one-third of the glomeruli exhibit ischemic thickening and wrinkling of the capillary basement membranes. The silver stain shows focal double contours as well as spikes and bubbling along the basement membranes. No wire loops are identified. Three glomeruli exhibit mesangiolysis with capillary thrombosis. PASH and trichrome stains show edema with patchy moderate severe interstitial fibrosis and tubular atrophy. There is patchy mild interstitial inflammation, and mild focal tubulitis is identified. The arterioles and small arteries are markedly thickened with obliteration of many of the lumina. There are abundant intimal and luminal deposits of glassy eosinophilic material, which is fuchsinophilic in the trichrome-stained section. The endothelium is swollen and denuded, and there is smudgy degeneration of myocytes, without inflammatory infiltration of the vessel wall. Several arterioles are occluded by fibrin thrombi, and there are red cell fragments in the swollen intima.

===Immunofluorescence===
fibrin thrombi, and there are red cell fragments in the swollen intima.

Immunofluorescence:
There are twenty glomeruli per section. Four contain cellular crescents. There is diffuse granular staining in the mesangium and along the capillary loops that is graded 4+ for IgG and light chains and 1+ for C1q. There is focal segmental staining that is graded 1+ for IgM and C3. There is no glomerular staining for IgA or albumin. There is diffuse staining in the vessels that is graded 4+ for IgG and light chains and 1+ for C1q and C3. There is diffuse 2+ staining for IgG and light chains along the tubular basement membranes; there is also 2+ focal staining for IgM, C1q and C3.

===Electron Microscopy===
Three thick sections containing a total of six glomeruli are available. Three contain cellular crescents. Ultrastructural examination of three glomeruli reveals moderately increased mesangial matrix with numerous small mesangial deposits. The capillary basement membranes are moderately thickened and contain numerous subendothelial deposits. There is focal expansion of the subendothelial space with pale "fluffy" material. Rare small subepithelial deposits are also noted. The foot processes are completely effaced. Tubular basement membranes contain numerous deposits as well.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Diffuse proliferative lupus nephritis with 24% crescents (WHO class IV.
- Lupus vasculopathy.
- Thrombotic microangiopathy.

This is an extremely active lesion, and the finding of lupus vasculopathy as well as thrombotic microangiopathy is associated with an even more ominous prognosis. Furthermore, there is already moderate tubulointerstitial scarring. However, only 6% of the glomeruli are globally sclerotic, so there is still some potential for recovery of renal function.

</spoiler>

CRP-28

2026-10-08T14:31:34Z

Peter Anderson:

'''CRP-28'''
==Clinical History==
The patient is a 58 year old male. Positive anti-dsDNA (221). Creatinine 0.6, creatinine clearance 104 ml/min, urinary protein 1.125 g/day. C3 = 44, C4 = 4.

==Gross Description==
Received in Zeus fixative are three cores measuring 3, 10 and 11 mm in length and 1 mm in diameter. These are entirely submitted for immunofluorescence. Received in Carson's fixative are three cores measuring 12, 14 and 17 mm in length and 1 mm in diameter. Six 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-028 H&E===
<peir-vm>specialcrp/CRP-028_HE</peir-vm>
===Case CRP-028 PASH===
<peir-vm>specialcrp/CRP-028_PASH</peir-vm>
===Case CRP-028 Silver===
<peir-vm>specialcrp/CRP-028_Silver</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of two fragments of renal medulla and three fragments of renal cortex. There are seventy-eight glomeruli in the three levels, which present a range of morphology. Seven are globally sclerotic, six demonstrate segmental sclerosis two contain cellular crescents, and twenty-seven show segmental necrosis. The remaining glomeruli show minimal mesangial expansion and proliferation. The silver stain shows occasional capillary loops with subendothelial deposits, but there is no splitting of the basement membranes. No spikes are noted along the epithelial surfaces. The PASH and trichrome stains show mild focal interstitial fibrosis and tubular atrophy. There is no interstitial edema, and there is no interstitial inflammation. The vasculature is well sampled and is unremarkable.

===Immunofluorescence===
There are eleven glomeruli in the sections. None of these are obsolete. There is diffuse granular mesangial staining that is graded 2+ for IgG, IgM, IgA, Clq, C3 and Kappa. There is 1+ mesangial staining for lambda. There is focal and segmental l+ staining along the capillary loops for all of these reagents. There is no staining of the vessels. Tubular basement membranes show focal 1+ staining for IgG and light chains. Tubular epithelial nuclei are strongly positive for IgG and light chains.

===Electron Microscopy===
Three thick sections containing a total of three glomeruli are available. Two show segmental necrosis. Ultrastructural examination reveals mild increase in mesangial matrix, although numerous mesangial electron dense deposits are identified. The capillary basement membranes are focally thickened, and there is focal fusion of the foot processes. The loops in the necrotic segments contains numerous large subendothelial deposits, and occasional smaller subendothelial deposits are noted in other loops. No subepithelial or intramembranous deposits are noted.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Focal necrotizing and sclerosing lupus nephritis, WHO class 3-B.

These features are most consistent with focal necrotizing and sclerosing lupus nephritis, which corresponds to WHO Class 3-B. The lesion is quite active, as shown by the numerous examples of segmental necrosis as well as subendothelial deposits. Unfortunately, the extent of segmental glomerular necrosis suggests that widespread segmental glomerulosclerosis is inevitable. However, there is currently only mild tubulointerstitial scarring.

</spoiler>

CRP-27

2026-10-08T14:31:03Z

Peter Anderson:

'''CRP-27'''
==Clinical History==
The patient is a 74 year old white male. Negative SPEP and UPEP; positive UIFE for kappa and lambda like chains. ANA 1:2560, C3 28 (decreased). C4 22. Negative bone marrow biopsy. No history of SLE. Creatinine 8, creatinine clearance 11 ml/min, urinary protein 0.798 g/day.

==Gross Description==
Received in transport medium are two cores chat measure 5 and 15 mm in length and 2 mm in diameter. Three 1-mm pieces are taken for EM, and the remainder is bisected and equally divided for immunofluorescence and light microscopy.

==Pathology==
===Case CRP-027 H&E===
<peir-vm>specialcrp/CRP-027_HE</peir-vm>
===Case CRP-027 PASH===
<peir-vm>specialcrp/CRP-027_PASH</peir-vm>
===Case CRP-027 Silver===
<peir-vm>specialcrp/CRP-027_Silver</peir-vm>
===Case CRP-027 Trichrome===
<peir-vm>specialcrp/CRP-027_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of three fragments of renal cortex, one of which has capsule on one end. There are fifty-six glomeruli in the three levels. Ten of these are globally sclerotic, but the remaining glomeruli are similar and show only very mild increase in mesangial matrix and no significant mesangial proliferation. The capillary basement membranes are unremarkable with the silver stain. There are no crescents, and no glomerular necrosis is identified. The PASH and trichrome stains show diffuse severe interstitial fibrosis and tubular dropout. Almost all of the remaining tubules are severely atrophic with markedly thickened and wrinkled basement membranes. There are numerous mononuclear inflammatory cells throughout the fibrotic interstitium, and in some areas they form large aggregates. Occasional examples of emperipolesis are identified. Overall, there is mild arteriolosclerosis, but a few arterioles show moderate thickening. There is no thrombosis, and no vasculitis is identified.

===Immunofluorescence===
There are eleven glomeruli in the sections, although two are obsolete. There is l+ focal and segmental mesangial staining for IgG, IgM, Clq, C3 and light chains. There is no mesangial staining for IgA or albumin. There is no staining along the glomerular basement membranes for any of these reagents. There is 4+ diffuse interstitial and tubular basemen t membrane staining for IgG, Clq and light chains. There is also focal staining for IgG and light chains in the tubular epithelial nuclei. There is no staining of the vessels.

===Electron Microscopy===
Four thick sections containing a total of three glomeruli are available. Ultrastructural examination of two glomeruli reveals mild increase in mesangial matrix, and occasional mesangial electron dense deposits are identified. The glomerular basement membranes are not significantly thickened, and the foot processes are generally intact. Tubular basement membranes are markedly thickened, and numerous dense deposits are noted within the tubular basement membranes. No deposits are noted along the glomerular basement membranes.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Mesangial lupus nephritis (WHO II-b) with severe chronic tubulointerstitial nephritis and fibrosis.

This is a striking biopsy. The immunofluorescence and electron microscopic findings are most consistent with lupus nephritis. However, the glomerular injury is relatively mild, while the tubulointerstitial injury is severe. In most instances of tubulointerstitial immune deposits, the associated tubular atrophy, interstitial fibrosis, and inflammation accompanies severe glomerular lesions. It is quite rare for severe tubulointerstitial damage to occur with only trivial glomerular lesions. The severity of tubulointerstitial scarring suggests that significant recovery of renal function is very unlikely.

</spoiler>

CRP-26

2026-10-08T14:30:46Z

Peter Anderson:

'''CRP-26'''
==Clinical History==
The patient is a 37 year old black female. SLE, pericardial effusion and acute renal failure. Currently on hemodialysis. Has received pulse steroids for 3 weeks. BUN 46, creatinine 6.

==Gross Description==
Received in transport media is one tapering core that measures 4 mm in length and 2 mm at the widest end. The core is bisected at the larger end, and two 1-mm pieces are submitted for electron microscopy. The remaining tissue is submitted for light microscopy. Note that no tissue is submitted for immunofluorescence.

==Pathology==
===Case CRP-026 H&E===
<peir-vm>specialcrp/CRP-026_HE</peir-vm>
===Case CRP-026 PASH===
<peir-vm>specialcrp/CRP-026_PASH</peir-vm>
===Case CRP-026 Silver===
<peir-vm>specialcrp/CRP-026_Silver</peir-vm>
===Case CRP-026 Trichrome===
<peir-vm>specialcrp/CRP-026_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy:===
The specimen consist of a fragment of renal cortex that contains 44 glomeruli in the three levels. Nine of these are obsolete, and two contain fibrocellular crescents. All of the nine obsolete glomeruli demonstrate severe ischemic atrophy with marked thickening and wrinkling of the glomerular basement membranes. In addition to the ischemic changes in the basement membranes, however numerous spike-like projections and holes are also noted. Overall the glomeruli have a somewhat hypocellular appearance, with striking increase in mesangial matrix but no mesangial cell proliferation. There is diffuse moderate interstitial fibrosis with corresponding tubular atrophy. There are focal mononuclear cell infiltrates, but tubulitis is not noted. The vessels show striking mucoid intimal fibrous thickening, and the larger arteries show prominent “onion-skinning”. All of the lumina have been obliterated. Some of the vessels contain fibrin thrombi, and most also contain trapped red cells and fibrin in the vessel walls. This change involves the arterioles as well as the small interlobular-sized arteries. Several glomeruli contain red cells in Bowman's space, and red cells are noted in occasional tubules.

===Immunofluorescence===
No tissue submitted.

===Electron Microscopy===
Two thick sections containing a total of six glomeruli are available, but one of these is obsolete, and another shows prominent periglomerular sclerosis. The other four are similar to those described above and show marked ischemic atrophy and increased mesangial matrix. Ultrastructural examination reveals extremely thickened and wrinkled capillary basement membranes, and numerous subepithelial and intramembranous electron dense deposits are identified. No subendothelial deposits are noted. Mesangial areas contain markedly increased amounts of matrix, and small mesangial deposits are also noted. There is complete effacement of the epithelial cell foot processes.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Thrombotic microangiopathy. Membranous lupus nephritis (WHO class V).

These findings are most consistent with a thrombotic microangiopathy superimposed on membranous lupus nephritis vascular lesions are relatively uncommon in lupus nephritis, but thrombotic microangiopathy is one of the patterns that has been described in association with lupus. In this particular case, it is not clear if the vascular lesion is secondary to lupus or represents a primary thrombotic microangiopathy. This type of vascular lesion is not specific, and the differential diagnosis includes malignant hypertension, hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura. The involvement of the arterioles as well as the small arteries makes scleroderma less likely. The severity of the vascular disease is consistent with an extremely poor prognosis for this kidney.

</spoiler>

CRP-25

2026-10-08T14:30:23Z

Peter Anderson:

'''CRP-25'''
==Clinical History==
The patient is a 34 year old female. BUN 8, creatinine 0.7, creatinine clearance 125 ml/min, and urinary protein 6.5 g/24 hr. BP: 116/75. Clinical Impression: Lupus nephritis.

==Gross Description==
Received in Zeus fixative is one core measuring 8 mm in length and 1 mm in diameter. It is entirely submitted for immunofluorescence. Received in Carson's fixative are two cores measuring 10 x 1 mm and 8 x 0.5 mm. Three 1-mm pieces are taken for EM, and the remainder is submitted for light microscopy.

==Pathology==
===Case CRP-025 H&E===
<peir-vm>specialcrp/CRP-025_HE</peir-vm>
===Case CRP-025 PASH===
<peir-vm>specialcrp/CRP-025_PASH</peir-vm>
===Case CRP-025 Silver===
<peir-vm>specialcrp/CRP-025_Silver</peir-vm>
===Case CRP-025 Trichrome===
<peir-vm>specialcrp/CRP-025_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of two small fragments of renal cortex that contain forty-five glomeruli in the three levels. One of these is obsolete, but none show segmental sclerosis. All of the glomeruli show moderate mesangial expansion and proliferation, and 11 of the glomeruli also show segmental endocapillary proliferation, focal necrosis, and occlusion of the capillary loops. There is one epithelial crescent, and one fibrous crescent is also noted. No definite wire loops are identified in the glomeruli. There is mild patchy interstitial fibrosis, and there is focal mild tubular atrophy. There are no inflammatory infiltrates. The arterioles and small arteries show mild focal thickening, but they are otherwise unremarkable.

===Immunofluorescence===
There are two to six glomeruli in the sections. There is diffuse coarse granular staining along the capillary basement membranes that is graded 4+ for IgG, IgA and light chains, and 2+ for Clq and C3. There is diffuse mesangial staining that is graded l+ for IgG, IgM, IgA, Clq, C3 and light chains. There are numerous albumin droplets in the tubular epithelium. There is no staining of the tubular basement membranes or vessels.

===Electron Microscopy===
Three thick sections containing a total of five glomeruli are available. These are similar to those described above and show moderate mesangial expansion and proliferation as well as marked thickening of the capillary basement membranes. There is also segmental endocapillary proliferation in three of the glomeruli, but there are no crescents. Ultrastructural examination reveals numerous large subepithelial and intramembranous electron dense deposits throughout the glomeruli. This is accompanied by diffuse effacement of the epithelial cell foot processes. Several small subendothelial deposits are also identified in one peripheral capillary loop. The mesangial regions are expanded by increased matrix and cells, and they also contain numerous large mesangial and paramesangial deposits.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Focal proliferative and membranous lupus glomerulonephritis, WHO Class III + V.

These findings are most consistent with a mixed pattern of lupus nephritis. There appears to be long-standing membranous lupus glomerulonephritis, but there is now an additional much more proliferative component. The proliferation is still largely focal and segmental, rather than diffuse, which places this proliferative lesion in the WHO Class III category. Although the glomerular lesion is becoming much more active, there is only minimal tubulointerstitial scarring, and the vessels are still quite well preserved.

</spoiler>

CRP-24

2026-10-08T14:30:09Z

Peter Anderson:

'''CRP-24'''
==Clinical History==
The patient is a 29 year old female with probable lupus nephritis. Mild proteinuria and normal renal function.

==Gross Description==
Received in Zeus fixative are two cores measuring 7 and 8 mm in length and 1 mm in diameter. These are entirely submitted for immunofluorescence. Received in Carson's fixative are three cores measuring 6, 7 and 8 mm in length and 1 mm in diameter. Three 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-024 H&E===
<peir-vm>specialcrp/CRP-024_HE</peir-vm>
===Case CRP-024 PASH===
<peir-vm>specialcrp/CRP-024_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of three cores of renal cortex that contain 40 glomeruli in the three levels. Two of these are obsolete, and four show segmental sclerosis with adhesions to Bowman's capsule. The remaining glomeruli are all similar and show minimal mesangial expansion and focal very mild mesangial cell proliferation. There is no segmental proliferation. The silver stain shows basement membranes of normal thickness, although occasional small holes are noted in enface cuts through the basement membranes. There is mild interstitial fibrosis, but there is minimal tubular atrophy. A number of the tubules are dilated, and the epithelium shows mild simplification. However, no red cells or cellular debris are noted within the tubular lumina. There are no inflammatory infiltrates. The small arteries show mild intimal fibrosis, but are otherwise unremarkable.

===Immunofluorescence===
There are six glomeruli in the sections. None of these show segmental sclerosis, and none are obsolete. There is diffuse mesangial staining that is graded 1+ for IGG, C1q and kappa and lambda light chains. There is similar mesangial staining that is graded only trace for IgM, IgA, and C3. There is no staining of the capillary basement membranes. There is no staining of the tubular basement membranes or vessels.

===Electron Microscopy===
Three thick sections containing a total of six glomeruli are available. One of these contains a focus of segmental sclerosis, and another shows severe global atrophy and sclerosis. The other four are similar to those described above and show minimal mesangial expansion and hypercellularity. Ultrastructural examination reveals occasional small, ill-defined mesangial electron dense deposits. The capillary basement membranes are generally of normal thickness and there is only focal effacement of the epithelial cell foot processes. No subepithelial, intramembranous or subendothelial deposits are identified in the capillary basement membranes.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Mesangial lupus nephritis, WHO Class II.

These findings are most consistent with mild mesangial lupus nephritis, WHO Class II. There is no evidence for transition to a more active lesion. There is minimal irreversible tubulointerstitial damage.

</spoiler>

CRP-23

2026-10-08T14:29:54Z

Peter Anderson:

'''CRP-23'''
==Clinical History==
The patient is a 56 year old man. BUN 30, creatinine 1.7, urinary protein 6 g/24 hr. Low C3, positive anti-double stranded DNA. Suspect lupus nephritis.

==Gross Description==
Received in transport media are two cores measuring 16 and 10 mm in length and 1 mm in diameter. Two 1-mm pieces are taken for EM. Two pieces measuring 4 and 7 mm in length are taken for immunofluorescence, and the remainder is processed for light microscopy.

==Pathology==
===Case CRP-023 H&E===
<peir-vm>specialcrp/CRP-023_HE</peir-vm>
===Case CRP-023 PASH===
<peir-vm>specialcrp/CRP-023_PASH</peir-vm>
===Case CRP-023 Silver===
<peir-vm>specialcrp/CRP-023_Silver</peir-vm>
===Case CRP-023 Trichrome===
<peir-vm>specialcrp/CRP-023_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consist of two fragments of renal cortex that contain 47 glomeruli in the three levels examined. Two of these are obsolete. The remaining glomeruli are similar and show marked diffuse proliferation and accentuation of the lobular architecture. Several of the glomeruli also demonstrate segmental necrosis, and a number of thick eosinophilic capillary loops (wire loops) are noted. There are also numerous examples of mesangial interposition, which are especially obvious with the silver stain. However, no spike formation is identified along the epithelial surfaces. One small epithelial crescent is identified. There is diffuse mild interstitial fibrosis, although tubular atrophy is only mild and focal. There are no inflammatory infiltrates. The vessels are unremarkable.

===Immunofluorescence===
There are 13 glomeruli in the sections. There is diffuse granular staining in the mesangial regions and along the capillary basement membranes that is graded 2+ for IgG, IgM, IgA, Clq, C3 and light chains. There is also strong nuclear staining in the tubular epithelium for IgG and kappa light chain. Focal albumin droplets are noted in some of the tubular lumina. There is no staining of the tubular basement membranes or vessels.

===Electron Microscopy===
Two thick sections containing a total of five glomeruli are available. These are similar and show diffuse mesangial and endocapillary cell proliferation with compression of the capillary lumina. Ultrastructural examination confirms the presence of mesangial interposition, and numerous· large subendothelial deposits are noted. There are also many immune complex deposits in the mesangial regions. No subepithelial or intramembranous deposits are noted. There is diffuse effacement of the visceral cell foot processes.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Diffuse proliferative lupus nephritis, WHO class IV.

These findings are most consistent with diffuse proliferative lupus nephritis. Although the glomerular lesion is quite active, the degree of interstitial fibrosis is still relatively mild.

</spoiler>

CRP-22

2026-10-08T14:29:34Z

Peter Anderson:

'''CRP-22'''
==Clinical History==
The patient is a 20 year old female. Positive ANA; SLE clinically. BUN 40, creatinine 2.6, albumin 1.3. BP. 140/70.

==Gross Description==
Received in transport media are two core of renal tissue measuring 11 and 12 mm in length and 2 nun in diameter. A 1-mm fragment is taken from each core for EM. The remainder of the 11-mm fragment is submitted for immunofluorescence, and the remainder of the 12-mm fragment is submitted for light microscopy.

==Pathology==
===Case CRP-022 H&E===
<peir-vm>specialcrp/CRP-022_HE</peir-vm>
===Case CRP-022 PASH===
<peir-vm>specialcrp/CRP-022_PASH</peir-vm>
===Case CRP-022 Silver===
<peir-vm>specialcrp/CRP-022_Silver</peir-vm>
===Case CRP-022 Trichrome===
<peir-vm>specialcrp/CRP-022_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consist of a fragment of renal cortex with a small portion of medulla on one end. There are at least 35 glomeruli in the sections. About 40% of the glomeruli contain epithelial crescents of varying size. No fibrous crescents are present, although a few crescents are beginning to show early infiltration by fibroblasts and formation of new collagen. All of the glomeruli show varying degrees of hypercellularity. In some of the glomeruli the cellular proliferation is diffuse, while in other the lesion is more segmental. In the glomeruli with more segmental proliferation, the peripheral capillary loops are generally quite thickened and eosinophilic, suggestive of large subendothelial deposits (wire loops). A few small foci of necrosis with karyorrhexis are identified in some glomeruli. Some of the peripheral capillary loops are completely occluded by large masses of eosinophilic material, probably representing immune complex deposits. There is diffuse interstitial edema, although interstitial fibrosis appears to be mild and patchy. The interstitium contains numerous lymphocytes. Most of the tubules are well preserved, although a few show dilatation and epithelial simplification. The small arteries in the biopsy show no significant thickening, and the arterioles are unremarkable.

===Immunofluorescence===
There are fourteen glomeruli in the sections. Many of these contain thickened capillary basement membranes consistent with wire loop lesions. There is diffuse capillary and mesangial staining that is graded 4+ for IgM, IgA, C3 and kappa light chain. There is similar staining that is graded 2+ for IgG, Clq and lambda light chain. Tubular basement membranes show l+ granular staining for IgG, IgA, Clq, C3 and kappa light chain. There is strong nuclear staining of the tubuloepithelial cells for IgG and kappa and lambda light chains. There is no staining of the vessels.

===Electron Microscopy===
Two thick sections are available, but one contains no glomeruli. The other contains six glomeruli, and all are markedly abnormal. They show segmental hypercellularity and very thick capillary basement membranes. Ultrastructural examination confirms the thickening of the capillary basement membranes, and a number of examples of mesangial interposition are noted. Numerous subendothelial electron dense deposits are present in many of the peripheral loops, and some of them are massive. There is diffuse effacement of the visceral cell foot processes. Mesangial areas are markedly expanded by increased matrix and cells, and they also contain numerous electron dense deposits. Occasional small intramembranous and subepithelial deposits are identified. Tubular basement membranes contain occasional small electron dense deposits.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy- Diffuse proliferative lupus glomerulonephritis. WHO class IV.

These findings are most consistent with diffuse proliferative lupus glomerulonephritis. This appears to be an early lesion, since there is minimal interstitial or tubular damage in this biopsy, and no glomerulosclerosis was identified.

</spoiler>

CRP-21

2026-10-08T14:29:16Z

Peter Anderson:

'''CRP-21'''
==Clinical History==
The patient is an 80 year old male. Admitted with shortness of breath and generalized weakness. Microscopic hematuria was discovered during his workup, and subsequently a left renal mass was identified. He underwent left nephrectomy and pathologic examination revealed papillary renal cell carcinoma. On admission his BUN and creatinine were 16 and 1.3. However, the day after surgery they had risen to 21 and 1.6, 4 days later they were 29 and 3.6, and 7 days after that they were 53 and 6.1. ANCA serology negative. ANA positive.

==Gross Description==
Received from an outside Medical Center are five paraffin blocks, five slides stained with H&E, three slides stained with GMS, and one vial of Carson's fixative with several small fragments of tissue.

==Pathology==
===Case CRP-021 H&E===
<peir-vm>specialcrp/CRP-021_HE</peir-vm>
===Case CRP-021 PASH===
<peir-vm>specialcrp/CRP-021_PASH</peir-vm>
===Case CRP-021 Silver===
<peir-vm>specialcrp/CRP-021_Silver</peir-vm>
===Case CRP-021 Trichrome===
<peir-vm>specialcrp/CRP-021_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
One of the blocks was used to prepare additional sections, which were cut at two microns and stained with H&E, PASH, trichrome and Jones' methenamine silver. This sections contain over 100 glomeruli. Two glomeruli with segmental necrotizing lesions are identified, but the remaining glomeruli show minimal mesangial expansion without proliferation. The glomerular basement membranes are unremarkable with the silver stain. PASH and trichrome stains show very mild focal interstitial fibrosis and tubular atrophy in the most superficial cortex, but there is no significant interstitial fibrosis in the deeper cortex. The most striking feature in the section is the presence of numerous small arteries with necrotizing granulomatous inflammation. This is transmural arteritis with essentially complete destruction of the arterial wall. The inflammatory infiltrate consists of macrophages, lymphocytes and numerous eosinophils with occasional multinucleated giant cells. No thrombi are identified. The larger arteries show mild intimal fibrosis, but they are otherwise unremarkable.

===Immunofluorescence===
Sections were cut from the paraffin block, treated with Pronase digestion, and then stained with the usual panel of antibodies. There is no glomerular staining for IgG, IgM, IgA, C1q, C3, albumin or light chains. There is no staining in the vessels or tubular basement membranes.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, left nephrectomy: Pauci-immune, necrotizing granulomatous arteritis and focal necrotizing glomerulonephritis.

This is a very unusual case. It is striking that the vascular lesion is much more widespread than the glomerular lesion, which is quite mild and focal. A positive ANCA would have helped confirm the category of disease, but even with a negative ANCA I still consider it pauci-immune small vessel

</spoiler>

CRP-20

2026-10-08T14:27:51Z

Peter Anderson:

'''CRP-20'''
==Clinical History==
The patient is a 24 year old while male. Systemic sclerosis. Presented with acute renal failure and hypertension and is now on dialysis. Rule out scleroderma renal crisis. BUN 22, creatinine 4.3; normal complements. Urinalysis shows 3+ protein and 3+ blood.

==Gross Description==
Received in transport media are two cores measuring 11 and 14 mm in length and 2 mm in diameter. Three 1-mm pieces are submitted for EM, and the remaining tissue is bisected and equally divided for immunofluorescence and light microscopy.

==Pathology==
===Case CRP-020 H&E===
<peir-vm>specialcrp/CRP-020_HE</peir-vm>
===Case CRP-020 PASH===
<peir-vm>specialcrp/CRP-020_PASH</peir-vm>
===Case CRP-020 Silver===
<peir-vm>specialcrp/CRP-020_Silver</peir-vm>
===Case CRP-020 Trichrome===
<peir-vm>specialcrp/CRP-020_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
Sections contain two fragments of renal cortex. There are about forty-five glomeruli per level. All of the glomeruli are similar and show severe ischemic atrophy. They appear rather solid and hypocellular, and the mesangium has a peculiar fibrillar appearance. There is focal mesangiolysis with red cell fragments in the mesangium. The silver stain shows marked thickening of the glomerular basement membranes and numerous double contours along the capillary loops. A number of the glomeruli contain fibrin thrombi and fibrinoid necrosis in the capillary loops. PASH and trichrome stains show diffuse mild interstitial fibrosis and focal chronic tubular atrophy. There is also acute tubular injury, manifested by irregular dilatation, epithelial simplification and sloughing. There is mild interstitial inflammation, and occasional examples of tubulitis are noted. The most striking change in the biopsy is in the vessels. Virtually every arterial vessel, including arterioles, interlobular arteries, and small arcuate arteries, is affected. There is mucoid intimal thickening, and large masses of fibrin are present under the endothelium as well as in the lumina. There is also infiltration of thickened intima by red blood cells, many of which are fragmented. However, there is essentially no inflammation associated with these vascular lesions.

===Immunofluorescence===
There are twenty-eight glomeruli in the sections. There is 2+ focal and segmental mesangial staining for IgM, Clq and C3. There is no glomerular staining for IgG, IgA, albumin or light chains. There is C3 staining in the vessels. There is no staining of the tubular basement membranes.

===Electron Microscopy===
Three thick sections containing a total of twelve glomeruli are available. Ultrastructural examination reveals markedly increased mesangial matrix. The glomerular basement membranes are severely thickened and wrinkled. The subendothelial space is markedly expanded and contains loose granular material. The visceral cell foot processes are completely effaced, and many of the capillary loops are partially or completely denuded. No immune complex deposits are identified. Several vessels are completely occluded by masses of fibrin.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Scleroderma

These features are typical of scleroderma, and in conjunction with the clinical history are entirely consistent with scleroderma renal crisis. The presence of thrombosis in virtually all the vessels, coupled with secondary severe ischemic changes in the glomeruli and tubules, suggests that extensive scarring is inevitable. Significant recovery of renal function is very unlikely.

</spoiler>

CRP-19

2026-10-08T14:27:33Z

Peter Anderson:

'''CRP-019'''
==Clinical History==
The patient is a 38 year old female. Recent onset of possible TTP with renal failure. Plasmapheresis performed, but renal function has not improved. Grand mal seizure four days ago. BP 170/100, urinary protein 4.5 g/day. C-ANCA and P-ANCA negative. BUN 68.

==Gross Description==
Received in saline is one core measuring 15 x 2 mm. Three 1-mm pieces are taken for EM, and the remaining tissue is equally divided for immunofluorescence and light microscopy.

==Pathology==
===Case CRP-019 H&E===
<peir-vm>specialcrp/CRP-019_HE</peir-vm>
===Case CRP-019 PASH===
<peir-vm>specialcrp/CRP-019_PASH</peir-vm>
===Case CRP-019 Silver===
<peir-vm>specialcrp/CRP-019_Silver</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
Section contain one fragment of renal cortex with capsule on one end. There are forty-nine glomeruli in· the three levels. Two of these are obsolete, and the remainder show a range of morphology. Some of the glomeruli have a "solid” appearance with increased matrix and occluded capillary lumina. Others show segmental mesangiolysis and kaxyorrhexis. A few of the glomeruli contain capillary thrombi, and many of the capillary loops are markedly congested. The silver stain shows diffuse wrinkling and thickening of the glomerular basement membrane, and numerous double contours are identified. PASH and trichrome stains show diffuse mild interstitial fibrosis and focal mild tubular atrophy. There is also extensive acute tubular necrosis. There is minimal patchy interstitial inflammation. There is moderate arteriolosclerosis, and many of the arterioles are completely occluded by fibrin thrombi.

===Immunofluorescence===
There are three glomeruli in the sections. One glomerulus shows segmental staining for IgM, IgG, Clq and CJ. However, the remaining glomeruli show no significant staining. Visceral epithelial cells are swollen and contain protein droplets. There is no glomerular staining for IgA, albumin or light chains. There is no staining of the tubular basement membranes or vessels. Tubular epithelium contains numerous protein droplets that stain for IgG, C3, albumin and light chains.

===Electron Microscopy===
Six thick sections containing a total of four glomeruli are available, but two are globally sclerotic. Ultrastructural examination of the other two glomeruli reveals increased mesangial matrix and focal mesangiolysis. The glomerular basement membranes are markedly thickened, and the subendothelial space is markedly expanded in most of the capillary loops. The expanded space is filled with loose granular and fibrillar material. There is focal mesangial interposition. Most of the capillary are denuded, although occasional visceral epithelial cells are identified. No immune complex deposits are identified.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Thrombotic microangiopathy, consistent with thrombotic thrombocytopenic purpura.

These features are most consistent with thrombotic microangiopathy, which in this clinical setting most likely represents thrombotic thrombocytopenic purpura. The microvascular disease is severe, and there is also severe acute tubular necrosis. However, tubulointerstitial scarring is still relatively mild, suggesting that some recovery of renal function is possible.

</spoiler>

CRP-18

2026-10-08T14:27:05Z

Peter Anderson:

'''CRP-018'''
==Clinical History==
The patient is a 28 year old black female. History of SLE and mixed connective tissue disease. Postpartum (45 days ago); now admitted with hypertension, nephrotic sediment and acute renal failure. BUN 74, creatinine 2.2, creatinine clearance 48 ml/min, urinary protein 1.26 g/day. C3 and C4 normal, CH50 decreased, ANA positive, Smith positive, RNP positive. Urinalysis shows 3+ protein, 3+ blood, greater than 25 RBCs, 11 to 25 WBCs, RBC casts.

==Gross Description==
Received in transport media is one core measuring 15 mm in length and 2 mm diameter. A 5-mm fragment is taken for immunofluorescence, two 1-mm fragments are taken for EM, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-018 H&E===
<peir-vm>specialcrp/CRP-018_HE</peir-vm>
===Case CRP-018 PASH===
<peir-vm>specialcrp/CRP-018_PASH</peir-vm>
===Case CRP-018 Silver===
<peir-vm>specialcrp/CRP-018_Silver</peir-vm>
===Case CRP-018 Trichrome===
<peir-vm>specialcrp/CRP-018_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a fragment of renal cortex that contains ninety-seven glomeruli in the three levels. None of these are obsolete, and none show segmental sclerosis. However, seven demonstrate segmental necrosis and mesangiolysis, and several glomeruli contain intracapillary thrombi. Many of the glomeruli demonstrate ischemic atrophy. All of the glomeruli show mildly increased mesangial matrix and mild mesangial hypercellularity. The silver stain shows no spikes along the capillary loops or double contours. There is striking hypertrophy of the juxtaglomerular regions. The PASH and trichrome stains show diffuse moderate interstitial fibrosis and tubular atrophy. There is no interstitial inflammation. There are striking changes in the arterioles and small arteries. Most of the arterioles are extremely thick, and many demonstrate fibrinoid necrosis. There is no inflammation associated with this fibrinoid necrosis. Some of the thrombi in afferent arterioles extend into the hilar region of the glomerulus. Arteries of interlobular size and smaller arcuate arteries show severe mucoid intimal thickening with concentrically arranged myointimal cellular proliferation (“onionskin" lesion). This thickening has caused considerable reduction in the arterial lumina. Many of these vessels contain fibrin in the thickened intima as well as fragmented red blood cells.

===Immunofluorescence===
There are eight glomeruli in the sections. There is 1+ mesangial staining for IgG, IgM, C3 and light chains. There is no mesangial staining for IgA, Clq, or albumin. There is no staining of the glomerular capillary loops for any of these reagents. Blood vessels show amorphous staining for IgM, Clq and C3. There is focal staining for C3 in the tubular basement membranes. Tubular epithelium contains occasional albumin droplets. There is strong speckled staining for IgG, IgA and light chains in the tubular epithelial nuclei.

===Electron Microscopy===
Two thick sections containing a total of five glomeruli are available. Ultrastructural examination confirms the mild increase in mesangial matrix, and occasional small mesangial deposits are identified. There is mild diffuse thickening of the capillary basement membranes, but no subendothelial widening is noted. No deposits are noted along the capillary loops.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Scleroderma (scleroderma renal crisis) and mesangial glomerulonephritis, consistent with mixed connective tissue disease

This combination of immune complex-mediated mesangial glomerulonephritis with scleroderma vascular lesions is consistent with mixed connective tissue disease. However, the vascular lesion is by more the more serious, with features that are typical of sclerodermal renal crisis. Although there is no global or segmental glomerulosclerosis in this biopsy, the severity of the vascular injury suggest that such glomerular scarring is inevitable. Furthermore, there is already moderate tubular atrophy and interstitial fibrosis.

</spoiler>

CRP-17

2026-10-08T14:26:39Z

Peter Anderson:

'''CRP-017'''
==Clinical History==
The patient is a 72 year old male. Acute renal failure of unknown etiology. Creatinine 5.5, BUN 75, urinary protein 371 mg/day. Normal complements, ANA, RA and SPEP. Patient has recently taken some Advil, but exact amount is unknown. Urinalysis shows 10 to 15 RBCs per high powered field, broad granular casts and no cellular casts.

==Gross Description==
Received in saline are six cores measuring 6, 7, 12, 14, 10 and 14 mm in length and 1 mm in diameter. Four 1-mm pieces are taken for electron microscopy. Three cores measuring 12, 13 and 8 mm in length are submitted for immunofluorescence, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-017 H&E===
<peir-vm>specialcrp/CRP-017_HE</peir-vm>
===Case CRP-017 PASH===
<peir-vm>specialcrp/CRP-017_PASH</peir-vm>
===Case CRP-017 Silver===
<peir-vm>specialcrp/CRP-017_Silver</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of three fragments of renal cortex that contain fifteen glomeruli in the three levels. None of these are obsolete, and none show segmental sclerosis. The glomeruli generally appear atrophic with thickened and wrinkled capillary basement membranes. However, two glomeruli demonstrate segmental necrosis ac the vascular pole, probably representing vasculitis of the afferent arteriole. There are no cellular or fibrous crescents. The PASH and trichrome stains show diffuse moderately severe interstitial fibrosis and tubular atrophy. There is tremendous acute interstitial inflammation. Most of the cells are polymorphonuclear leukocytes with a small percentage of eosinophils. This is associated with numerous examples of mild tubulitis. The most striking feature of the biopsy is the large vessels. Several show transmural inflammation with severe fibrinoid necrosis. Some of the vessels show rupture into the adjacent parenchyma, which is accompanied by severe interstitial inflammation. The arterioles are mildly thickened but are otherwise unremarkable.

===Immunofluorescence===
There are eleven glomeruli in the sections. None of these contain crescents. There is 1+ focal and segmental mesangial staining for IgM, Clq and C3. There is no glomerular staining for IgG, IgA, albumin or light chains. There is no staining of the tubular basement membranes or vessels. There is focal staining for C3 in Bowman's capsule.

===Electron Microscopy===
Three thick sections containing a total of two glomeruli are available. Ultrastructural examination of these two glomeruli reveals focal thickening and wrinkling of the glomerular basement membranes. The subendothelial space is widened and filled with pale, loose granular material. There is mild increase in mesangial matrix. The epithelial cell foot processes are completely effaced. No electron dense deposits are identified.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Polyarteritis nodosa.

These features are most consistent with polyarteritis nodosa (macroscopic polyarteritis). This lesion is distinctly different from microscopic polyangiitis. In particular, ANCA serology is rarely positive in polyarteritis nodosa, and glomerulonephritis is rare. On the other hand, there are typically ischemic glomerular lesions, such as those described in this biopsy. Unfortunately, there is already moderately severe tubulointerstitial scarring. This scarring, in association with the severe necrotizing vasculitis, suggests that significant recovery of renal function is very unlikely.

</spoiler>

CRP-16

2026-10-08T14:26:24Z

Peter Anderson:

'''CRP-016'''
==Clinical History==
The patient is a 43 year old female. Malignant hypertension with progressive acute renal failure. BUN 64, creatinine 6.5, urinary protein less than 2 g/24 hr. BP 210/120.

==Gross Description==
Received in transport media are two cores measuring 6 and 7 mm in length and l mm in diameter. Three 1-mm pieces are taken for EM. The remainder of one core is submitted for immunofluorescence, and the other core is submitted for light microscopy.

==Pathology==
===Case CRP-016 H&E===
<peir-vm>specialcrp/CRP-016_HE</peir-vm>
===Case CRP-016 PASH===
<peir-vm>specialcrp/CRP-016_PASH</peir-vm>
===Case CRP-016 Silver===
<peir-vm>specialcrp/CRP-016_Silver</peir-vm>
===Case CRP-016 Trichrome===
<peir-vm>specialcrp/CRP-016_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of a small fragment of renal cortex that contains 70 glomeruli in the three levels. Twenty-two of these are obsolete. The others are similar and show striking ischemic atrophy with shrinkage of the glomerular tuft, increase in mesangial matrix and markedly thickened and wrinkled capillary basement membranes. The silver stain confirms the marked GBM thickening, but no spike formation or splitting is identified. There is diffuse mild interstitial fibrosis, but there is moderate diffuse tubular atrophy. There is also patchy chronic inflammation, and occasional examples of tubulitis are noted. The mononuclear cell infiltrate is primarily lymphocytic with only a few plasma cells and no eosinophils. The most striking change in the biopsy is the appearance of the vessels. The arterioles and small arteries are markedly thickened with almost complete obliteration of the lumina. The interlobular arteries show concentric fibrosis and elastic reduplication (onion skinning). Several of the interlobular arteries contain fibrin thrombi, and occasional red cells and red cell fragments are identified in the thickened intima. No vascular necrosis is identified.

===Immunofluorescence===
There are twelve glomeruli in the sections. Three of these are obsolete. There is 1+ mesangial staining for C3. There is no glomerular staining for IgG, IgM, IgA, Clq or light chains. Some of the tubules contain casts that stain for IgA and kappa and lambda. There is 2+ staining for C3 in the vessels.

===Electron Microscopy===
Three thick sections containing a total of nineteen glomeruli are available. Three are obsolete, but the others are similar and show marked ischemic atrophy. Ultrastructural examination confirms the generalized thickening and wrinkling of the capillary basement membranes. Some of the peripheral loops demonstrate widening of the subendothelial space. No electron dense deposits are identified in the capillary basement membranes or mesangial regions. Foot processes show only focal fusion.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Malignant nephrosclerosis.

These findings are most consistent with malignant nephrosclerosis. The severity of the vascular injury suggests a very poor prognosis for this kidney.

</spoiler>

CRP-15

2026-10-08T14:26:08Z

Peter Anderson:

'''CRP-15'''
==Clinical History==
The patient is a 55 year old female with vasculitic lesions on her legs. Skin biopsy showed leukocytoclastic vasculitis. Normal renal ultrasound. Hematuria. BUN 21, creatinine clearance 86 ml/min, urinary protein 1.7 g/day. ANA negative.

==Gross Description==
Received in saline are two cores measuring 15 and 18 mm in length and 1 to 2 mm in diameter. Three 1-mm pieces are taken for EM. Two cores measuring 6 and 9 nun in length are submitted for immunofluorescence, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-015 H&E===
<peir-vm>specialcrp/CRP-015_HE</peir-vm>
===Case CRP-015 PASH===
<peir-vm>specialcrp/CRP-015_PASH</peir-vm>
===Case CRP-015 Silver===
<peir-vm>specialcrp/CRP-015_Silver</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of multiple small fragments of rental cortex that contain forty-five glomeruli in the three levels. Two of these are obsolete, and the remainder show moderate mesangial expansion and hypercellularity. In addition to the diffuse mesangial proliferation, however, eleven glomeruli also demonstrate segmental necrosis and neutrophilic infiltration, and five glomeruli contain cellular crescents. There are no fibrous crescents. The silver stain shows segmental rupture of the capillary basement membranes in the areas of necrosis, but there are no spikes along the loops, and no double contours are noted. The PASH and trichrome stains show very mild focal interstitial fibrosis. The tubules are quite well preserved, and there are no inflammatory infiltrates. The vasculature is well sampled and is unremarkable.

===Immunofluorescence===
There are thirteen glomeruli in the sections. One glomerulus has a cellular crescent. There is diffuse mesangial staining that is graded 3+ for IgA, 1+ for IgG, C3 and light chains, and trace for IgM. There is no mesangial staining for Clq. There is no staining along the capillary loops or tubular basement membranes for any reagent. Tubular epithelium contains albumin droplets. There is no staining of the vessels.

===Electron Microscopy===
Three thick sections containing a total of two glomeruli are available. Ultrastructural examination reveals increased matrix and mesangial hypercellularity. Occasional mesangial electron dense deposits are identified. The capillary basement membranes are focally thickened, and there is also focal fusion of the visceral epithelial cell foot processes. Most of the capillary lumina are occluded by endothelial swelling and inflammatory cells. There is focal subendothelial fibrin deposition, but no immune complex deposits are noted along the capillary loops.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy- Henoch-Schönlein nephritis.

These features are most consistent with Henoch-Schonlein nephritis. Although the histologic features are essentially identical to IgA nephropathy, the presence of segmental necrotizing lesions and crescents is more typical of Henoch-Schonlein nephritis. Furthermore, this correlates much better with the clinical history of systemic small-vessel vasculitis. Although the glomerular lesion is quite active, there is no significant tubulointerstitial scarring.

</spoiler>

CRP-14

2026-10-08T14:25:50Z

Peter Anderson:

'''CRP-14'''
==Clinical History==
The patient is a 62 year old male. Acute renal failure, abnormal chest x-ray, and 4 to 5 month history of "sinusitis." Creatinine was 1.0 on 8/15/01 and has risen to 4.5 with BUN of 150. Nondiagnostic skin biopsy, nondiagnostic open lung biopsy and nondiagnostic sinus biopsy. C-ANCA 1:320, ANA 1:40 speckled. Anti-GBM pending.

==Gross Description==
Received in transport medium is one wedge-shaped fragment measuring 17 x 5 mm in greatest dimension. An 8-mm fragment is taken for immunofluorescence, seven 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-014 H&E===
<peir-vm>specialcrp/CRP-014_HE</peir-vm>
===Case CRP-014 PASH===
<peir-vm>specialcrp/CRP-014_PASH</peir-vm>
===Case CRP-014 Silver===
<peir-vm>specialcrp/CRP-014_Silver</peir-vm>
===Case CRP-014 Trichrome===
<peir-vm>specialcrp/CRP-014_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of two fragments of superficial renal cortex that contain eighty-one glomeruli in the three levels. Four of these are globally sclerotic, but none show segmental sclerosis. About 70% of the glomeruli contain segmental necrotizing lesions, and fifty-one glomeruli (63%) contain cellular crescents. Some of these crescents have ruptured through Bowman's space and are associated with periglomerular inflammation. The remaining uninvolved glomeruli show minimal mesangial expansion and no significant proliferation. The capillary basement membranes in these glomeruli are unremarkable with the silver stain. The PASH and trichrome stains show diffuse interstitial edema and at least mild interstitial fibrosis. However, there is only mild focal tubular atrophy. Occasional small collections of lymphocytes are present in the interstitium, and some of these are associated with mild tubulitis. The vasculature is well sampled. There is mild medial thickening and focal intimal fibrosis in the small arteries. There is no vasculitis, and no thrombosis is identified.

===Immunofluorescence===
There are twelve glomeruli in the sections. At least two of these contain cellular crescents. There is 2+ focal and segmental staining for C3, and there is trace focal and segmental staining for IgG, IgA and kappa. There is no glomerular staining for IgM, Clq, albumin or lambda. There is 2+ staining for C3 in the vessels. There is no staining of tubular basement membranes.

===Electron Microscopy===
Three thick sections containing a total of four glomeruli are available. One is obsolete, and two contain cellular crescents. Ultrastructural examination reveals compression of the glomerular tufts with marked segmental wrinkling of the capillary basement membranes. The foot processes over these loops are completely effaced. There is fibrin deposition in Bowman's space in association with the crescent. The uninvolved capillary loops show no significant thickening, and the foot processes are intact. No immune complex deposits are identified in the mesangium or along the capillary basement membranes.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy. Pauci-immune crescentic glomerulonephritis, consistent with Wegener's granulomatosis.

This pattern of pauci-immune crescentic glomerulonephritis is very typical of Wegener's granulomatosis, although an identical pattern may be seen in microscopic polyangiitis. The positive C-ANCA, as well as the clinical history of sinus involvement, is much more consistent with Wegener's than microscopic polyangiitis. Although there is mild tubulointerstitial scarring, significant recovery of renal function appears possible if the glomerular injury can be controlled.

</spoiler>

CRP-13

2026-10-08T14:25:27Z

Peter Anderson:

'''CRP-13'''
==Clinical History==
The patient is a 21 year old white female. BUN 56, creatinine 8.8, creatinine clearance 8 ml/min, urinary protein 3.4 g/day. Strongly positive anti-GBM. C-ANCA and P-ANCA negative. Previous biopsy showed "granulomatous glomerulonephritis. Immunofluorescence staining in that biopsy was suggestive of linear staining for IgG, but the background was reported as high, so a definite diagnosis of anti-GBM glomerulonephritis was not made.

==Gross Description:==
Received in transport medium are two cores measuring 12 and 15 mm in length and 2 mm in diameter. Four 1-mm pieces are taken for EM, and the remaining tissue is bisected and equally divided for immunofluorescence and light microscopy.

==Pathology==
===Case CRP-013 H&E===
<peir-vm>specialcrp/CRP-013_HE</peir-vm>
===Case CRP-013 PASH===
<peir-vm>specialcrp/CRP-013_PASH</peir-vm>
===Case CRP-013 Silver===
<peir-vm>specialcrp/CRP-013_Silver</peir-vm>
===Case CRP-013 Trichrome===
<peir-vm>specialcrp/CRP-013_Trichrome</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy</div>
<div class="mw-collapsible mw-collapsed" id="mw-customcollapsible-diagnosis">
<div class="mw-collapsible-content">

==Microscopic Description==
===Light Microscopy===
The specimen consists of four fragments of renal cortex that contain a total of sixty-three glomeruli in the three levels. Five of these are globally sclerotic, and the remaining glomeruli demonstrate exuberant crescent formation and marked compression of the glomerular tufts. About one third of the glomeruli also show segmental fibrinoid necrosis. There does not appear to be significant mesangial proliferation, and the glomerular basement membranes that are still intact show no spike formation or splitting. The PASH and trichrome stains show diffuse mild interstitial fibrosis, but there is minimal tubular atrophy. There is mild interstitial edema, and focal collections of mononuclear inflammatory cells are present. These are associated with occasional examples of tubulitis. The vasculature is adequately sampled and is unremarkable.

===Immunofluorescence===
There are nine glomeruli in the sections, and all of them contain large cellular crescents. There is diffuse linear staining along the capillary basement membranes that is graded 4+ for IgG and kappa and 1+ for lambda. There is also focal and segmental 1+ linear staining for C3 along the basement membranes. There is 1+ focal and segmental mesangial staining for IgM. There is no mesangial staining for IgG, IgA, Clq, C3 or light chains. There is no staining of the tubular basement membranes. There is 1+ staining for C3 in the vessel walls.

===Electron Microscopy===
Three thick sections containing a total of six glomeruli are available. All of these contain large cellular crescents, and there is also focal necrosis. Ultrastructural examination reveals marked compression of the glomerular capillaries, and the foot processes are completely effaced. Occasional breaks in the glomerular basement membranes are identified. There are no electron dense deposits in the glomeruli.

</div></div>

<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy - Anti-GBM glomerulonephritis.

These findings are most consistent with anti-glomerular basement membrane glomerulonephritis. Although there is still relatively mild tubulointerstitial scarring, the severity and extent of the glomerular lesions suggest that progression of the lesion with significant scarring is inevitable.

</spoiler>