A 58-year-old woman with multiple masses, which rapidly developed 2 months prior on her face, was referred to the dermatology department. She complained of occasional itching and tingling sensations. She had no remarkable medical or familial history except hypothyroidism. Physical examination revealed well-demarcated, firm, erythematous-to-brownish masses on her forehead and left postauricular area ( Fig. 1). Initial laboratory tests showed normal results.
Histopathological FindingsPunch biopsies of the forehead and postauricular masses showed diffuse nodular infiltrates sparing the epidermis. The tumor cells had varying morphologies, ranging from epithelioid to spindled appearance. Large epithelioid cells had abundant pale eosinophilic cytoplasm and eccentric nuclei with vesicular chromatin and prominent nucleoli. Spindle cells with elongated nuclei were arranged in a fascicular pattern. High mitotic rates with marked nuclear pleomorphism were noted on higher magnification (Fig. 2). On immunohistochemical staining, malignant cells were positive for leukocyte common antigen, CD4, CD68, and CD163 (Fig. 2) but negative for CD1a, CD3, CD8, CD20, CD21, CD30, CD34, CD35, CD56, CD117, CD123, CD138, epithelial membrane antigen, langerin, myeloperoxidase, HMB-Figure 2 (a, b) Histopathological staining revealing diffuse infiltration of tumor cells in the whole dermis (a: hematoxylin-eosin, 940, b hematoxylin-eosin, 9100). (c) Tumor specimen comprising round cells with nuclear pleomorphisms (hematoxylin-eosin, 9400). (d-g) Tumor cells showing immunoreactivity for CD68, CD163, CD4, and leukocyte common antigen (9400). (h) Immunohistochemical staining of Ki-67 demonstrating high proliferative rates (approximately 70%) (Ki-67, 9400) (a) (b) (c) Figure 1 Multiple erythematous masses were noted on the forehead (a,b) and postauricular area (c) ª