Primary cutaneous extra-nodal NK-cell lymphoma, nasal type

Primary extra-nodal NK-cell lymphoma of skin is extremely rare. A 55-year-old man presented with an elevated plaque of trunk. The dermatologists’ diagnosis was sporotrycosis and a biopsy was taken, which showed diffuse dense infiltrations of medium-sized and large atypical malignant lymphocytes. Epidermal hyperplasia and erosions were also seen. Immunohistochemically, the atypical lymphocytes were positive for CD45, CD56, CD57, p53 and Ki-67 (labeling index = 82%). They were negative for CD20, CD79, CD10, bcl-2, κ-light chain, λ-light chain, CD3, CD4, CD5, CD21, CD23, CD38, CD43, CD68, CD138, CD15, CD30, TdT, and cyclin D1. EBER was positive. The pathological diagnosis was primary cutaneous NK-cell lymphoma, nasal type. The post-biopsy blood test identified no leukemia findings. Post-biopsy imaginings revealed no mass and lymphadenopathy in the body. The skin lesions of the patient almost improved (complete remission) by chemotherapy (CHOP) followed by local radiation, and the patient is now followed up.