Cutaneous lymphadenoma: an adnexal neoplasm with intralobular activated lymphoid cells.

Cutaneous lymphadenoma is an uncommon epithelial neoplasm with a controverted adnexal differentiation. We report a typical case of cutaneous lymphadenoma that developed on the left cheek of a 18-year-old woman. Histologically, the neoplasm consisted of lobules of basaloid cells with a peripheral palisading array and filled with a lymphocyte-predmoninant mixed cellular population. Numerous intralobular cells with ample amphopilic cytoplasm, large vesicular nuclei, and prominent nucleoli also were noticed. Immunohistochemical study showed labeling of these Reed-Sternberg-like large cells by antibodies against CD30 antigen. Our findings suggest that cutaneous lymphadenoma is a poorly differentiated adnexal neoplasm, probably trichoblastoma-related, where a singular interaction with several immune cells is established, including activated large lymphocytes analogous to those malignantly proliferating in Hodgkin's disease.