CD5 + Gamma Delta T-Cell Lymphoproliferative Disorder/Lymphoma Without Cytotoxic Granules in the Skin.

We report a case of an unusual and aggressive gamma delta T-cell lymphoproliferative disorder/lymphoma presenting in the skin that lacked the expected cytotoxic markers and had increased expression of CD5, CD20, CD79a, CD30, and PD-1 without CD56. Monoclonal TCR-γ gene rearrangement was identified. A computed tomography scan of the chest, abdomen, and pelvis revealed a 7.7-cm soft-tissue inguinal mass and prominent retroperitoneal and pelvic lymphadenopathy, without hepatosplenomegaly. Flow cytometry finding on peripheral blood was normal. The clinical, morphologic, and immunophenotypic features of this case defy the current World Health Organization and European Organization for Research and Treatment of Cancer classifications, and a similar case has not been reported previously.