gamma delta T-cell lymphoma: a clinicopathologic study of 6 cases including extrahepatosplenic type.

We report 6 cases of gamma delta T-cell lymphoma (GDTL) among 115 peripheral T-cell lymphomas over a 12-year period. All patients exhibited extranodal lymphomas, comprising 3 hepatosplenic, 1 cutaneous, 1 intestinal, and 1 thyroidal lymphoma. Despite therapies, all but 1 patient died of disease within 16 months of diagnosis. The cytologic features of lymphoma cells in 4 of 5 cases examined were very similar: coarsely reticulated nuclear chromatin, multiple small nucleoli, abundant faintly eosinophilic granular cytoplasm, and focal angiocentric proliferation. All 6 lymphomas showed Cd3+CD4-CD8-/+ phenotype. CD56 was positive in 3 cases, 1 of which was also CD16 positive. Perforin and T-cell intracellular antigen-1 were positive in all 5 cases examined. Southern blot analysis revealed clonal gene rearrangements of the T-cell receptor delta-chain gene in all 5 cases examined. Based on these findings, together with a review of the literature, GDTLs seem to have several common lineage-specific features, although clinical presentation and course of GDTL are heterogeneous.