Blastic Natural Killer-Cell Lymphoma Presenting in the Skin

Blastic natural killer (NK)-cell lymphoma is a clinically aggressive hemato-logic neoplasm with a high incidence of cutaneous involvement. We report a 19-year-old man who presented with asymptomatic, erythematous, infiltrated bean plaques and nodules of various sizes, scattered over the face, trunk and extremities. A skin biopsy specimen revealed diffuse dermal infiltration of medium-sized pleomorphic cells with a blastic appearance. Immunohistochemical studies showed that the tumor cells were positive for CD56, CD43, CD123, and terminal deoxynucleotidyl trans-ferase (TdT). The neoplastic cells were negative for B-cell, T-cell, and myeloid cell markers. In situ hybridization for Epstein-Barr virus encoded RNA (EBER) gave a negative result. Flow cytometric analysis of bone marrow aspirate demonstrated a CD56 positive population of blastic cells. A diagnosis of blastic NK-cell lymphoma was made and the skin lesions regressed after treatment with L-asparaginase-based chemotherapy (L-asparaginase, cyclophosphamide, etoposide). The skin lesions regressed after two sessions of chemotherapy.