PMC4058994_01
Clinical and Microscopic Images of the Illustrative Case. A, Shiny 2 x 3-cm violaceous nodule displaying a golden contusiform rim, located on the left deltoid. B, Corresponding histopathologic image (hematoxylin-eosin [H&E], original magnification, x100): dense infiltrate of tumor cells in the upper and lower dermis. C, A x400 magnification of the infiltrate shows monomorphous medium-sized cells with slightly irregular nuclei, finely dispersed chromatin, and scant cytoplasm. D, Tumor cells infiltrating upper dermis are associated extensive extravasation of erythrocytes (H&E, original magnification, x200).
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F1
Our study was initiated by the results of the immunohisto-chemical (IHC) analysis of a violaceous nodule with surrounding golden contusiform rim on the shoulder of an otherwise asymptomatic 80-year-old man (Figure 1A). Histopathologic examination revealed a dense dermal infiltrate of uniform, mononuclear cells in the absence of other inflammatory cells, necrosis, or angioinvasion (Figure 1B).
Immunohistochemical Staining of Formalin-Fixed Paraffin-Embedded Sections of the Lesion Shown in Figure 1. Diaminobenzidine, original magnification, x200: CD56 (A), CD4 (B), CD123 (C), and CD31/PECAM-1 (platelet endothelial cell adhesion molecule 1) (D).
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F2
Samples stained for IHC analysis were positive for CD4, CD56, CD123, and CD31 (Figure 2) and negative for CD2, CD3, CD5, CD7, CD8, T-cell-restricted intra-cellular antigen 1 (TIA-1), CD20, PAX-5, lysozyme, myeloper oxidase, CD30, CD1a, CD68, and terminal deoxynucleotidyl transferase. Tumor cells demonstrated strong immunoreactivity in 6 cases, paralleling the IHC results seen in Figure 2, whereas 2 cases had negative results.