Hepatosplenic γδ T-cell lymphoma: a distinctive aggressive lymphoma type

The T-cell receptor (TCR) expressed on the surface of most T-lymphocytes is of αβ type, and only a minority bear the γδ-TCR. Similarly, postthymic T-cell lymphomas rarely express γδ-TCR. Hepatosplenic γδ T-cell lymphoma is an uncommon entity that has so far not been widely recognized. We report one such case that has been comprehensively studied by multiple modalities and showed the unique occurrence of leukemic picture at presentation. The 39-year-old man presented with fever, marked weight loss, and massive splenomegaly. Peripheral blood showed thrombocytopenia and a white cell count of 5.8 x 10 9 /l, with 66% medium-sized lymphoid cells that had a round or folded nucleus, condensed chromatin and a moderate amount of pale blue cytoplasm. Splenectomy was performed and histologic examination of the spleen, bone marrow, liver, and abdominal lymph nodes demonstrated lymphoma infiltration with a predominantly sinusoidal pattern. Immunohistochemical studies of the lymphoma cells showed a T-cell phenotype: CD2 + CD3 + CD5 + CD7 + γδ-TCR + αβ-TCR - CD56 + CD4- CD8- CD16- CD57-. Cytogenetic studies showed complex clonal chromosomal abnormalities of 44,X,-Y,-11,-22, + mar in 3/16 cells. Rearrangement of the TCR γ chain gene was demonstrated by polymerase chain reaction; the TCR β chain gene was partially rearranged. The patient did not respond to single agent chemotherapy, but achieved clinical remission with combination chemotherapy. Based on the available data in the literature, hepatosplenic γδ T-cell lymphoma exhibits distinctive clinicopathologic features, and probably represents the neoplastic counterpart of splenic γδ T-lymphocytes. This disease is associated with a poor prognosis and usually relapses despite initial response to chemotherapy.