| Abstract: | CD20‐positive natural killer (NK)/T‐cell lymphoma is extremely rare. We describe a case of a CD20‐positive nodal NK/T‐cell lymphoma with cutaneous involvement in a 32‐year‐old man. The patient presented with fever, night sweats, right inguinal lymphadenopathy and multiple violaceous to erythematous nodules and plaques on the back and bilateral legs. Immunohistochemical analysis showed diffusely and strongly positive staining for CD3, CD3 epsilon, CD43, CD56, TIA‐1 and CD20 but negative staining for other B‐cell markers, including CD79a and PAX‐5 and T‐cell markers CD5 and CD7. The tumor cell nuclei were diffusely positive for Epstein–Barr virus‐encoded RNA in situ hybridization. A partial clinical response was observed after chemotherapy, indicated by the decreased size of the lymph nodes and skin lesions. It is a diagnostic challenge to deal with lymphoma cells that present with the surface proteins of both T‐ and B‐cells. |
