IPLab:Lab 9:RMSF

Clinical Summary

This 9-year-old child was admitted with headache, fever, and a morbilliform rash on the arms and legs. There was a history of a tick being removed from her back. By the time a biopsy was performed, the rash had become petechial. Antibiotics were given and the child recovered within one week.

Biopsy Findings

A skin biopsy of this patient's lesion was stained with hematoxylin and eosin. A different section was also stained with an immunoperoxidase technique using antibody against Rickettsia rickettsii. Organisms were demonstrated in the endothelial cells.

Images

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  This is a low-power photomicrograph of the skin biopsy. Note areas of hemorrhage (arrow) in the dermis.
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  This is a higher-power photomicrograph demonstrating areas of hemorrhage immediately underneath the epidermis. Also note the cellularity and thrombosis of the small vessels in the dermis (arrow).
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  This is a photomicrograph of a small vessel in the dermis which is demonstrating mild vasculitis.
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  This is a higher-power photomicrograph of a dermal vessel with mild vasculitis.
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  This is a photomicrograph of dermis with an area of more severe vasculitis (arrow).
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  This is a high-power photomicrograph of severe vasculitis in the dermis.
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  This is a high-power photomicrograph of a dermal vessel (arrow) which is exhibiting vasculitis and thrombosis.
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  This is a high-power photomicrograph of a thrombosed vessel in the dermis. Note that the endothelial cells are missing along part of the circumference of the vessel (arrows)--this is where the main part of the thrombus has attached. Also note the inflammation surrounding the vessel.

Morbilliform means measles-like.

A thrombus is a solid mass resulting from the aggregation of blood constituents within the vascular system.