Gamma delta T-cell neoplasms: a clinicopathological study of 11 cases.

BACKGROUND: The majority of T-cell neoplasms express T-cell antigen receptor (TCR) alpha beta on their cell surface, and a few cases show the TCR gamma delta phenotype. Recently, a variety of gamma delta T-cell neoplasm was recognized; however, its clinicopathological features have not been extensively analyzed. Here we report the results of a clinicopathological study of 11 cases of gamma delta T-cell neoplasm.

PATIENTS AND METHODS: During the 11-year period from 1989 to 1999, 104 patients with T-cell neoplasms were examined by flow cytometric analysis and/or immunohistochemical analysis. Tumor cells from all 104 patients expressed one or more of the T-cell antigens-CD2, CD3, CD5 and CD7. Forty-nine of the 104 cases of T-cell neoplasms were examined immunophenotypically for TCR alpha beta/gamma delta subsets.

RESULTS: Expression of TCR gamma delta on tumor cells was found in five (33%) of 15 patients with precursor T-cell lymphoblastic leukemia/lymphoma, one (25%) of four with T-cell granular lymphocytic leukemia and five (26%) of 19 with peripheral T-cell lymphoma (PTCL), whereas no expression was found in 11 patients with adult T-cell leukemia-lymphoma. Primary sites of the five patients with gamma delta PTCL were as follows: lymph node, three; skin, one and liver, tonsil and skin, one. The courses of the three patients with gamma delta PTCL of nodal onset were very short (3, 5 and 9 months, respectively), and they were all resistant to combination chemotherapies.

CONCLUSIONS: Although gamma delta T-cell neoplasm constitutes a heterogeneous population, it is important to examine the expression of TCR with the view to identifying possible poor prognostic subgroups, such as primary nodal gamma delta T-cell lymphoma.