Image 1-Low power magnification shows a diffuse dermal infiltrate.


Image 2-The infiltrate is separated from the epidermis by a Grenz zone.

Image 3-Mononuclear cells are interspersed with extravasated red blood cells.

Image 4-The mononuclear cells are small and mitotically active.


Image 5-All of the cells are diffusely positive for CD45 (Leukocyte common antigen) and negative for cytokeratin and S100.

Image 6-Diffuse positivity for CD56 (natural killer cell phenotype)

Image 7-Diffuse positivity for CD68.

Image 8-Diffuse positivity for myeloperoxidase (MPO).

The tumor cells were negative for CD3, CD20, CD33, CD34, CD79a, CD99, CD117, and TdT.

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Case Study

This is a 85 year old woman who presents with multiple ecchymotic plaques on the upper trunk.