γδ T-cell lymphoma of the skin -: A clinical, microscopic, and molecular study

Background: Only a few cases of primary gamma delta cutaneous T-cell lymphoma (CTCL) have been reported. We encountered 3 cases of this rare condition. Objectives: To characterize gamma delta CTCLby clinical, microscopic, and molecular methods and to investigate the role of Epstein-Barr virus (EBV) infection in its pathogenesis. Design: Patients were evaluated by clinical examination. and biopsy specimens of lesional skin were examined by light microscopy and immunohistochemistry. Polymerase chain reaction amplification for T-cell receptor gamma gene rearrangements and in situ hybridization for EBV were performed on 3 biopsy specimens. Setting: National Institutes of Health, a tertiary referral center. Patients: Individuals with a clinical and histologic diagnosis of primary gamma delta CTCL. Outcome Measures: Clinical, light microscopic, and immunohistochemical features, and the presence of T-cell rearrangement and EBV RNA in biopsy specimens. Results: Patients exhibited multiple plaques, tumors, and/or subcutaneous nodules primarily distributed over the extremities, Individuals exhibited an aggressive clinical course with resistance to multiagent chemotherapy and radiation. Microscopic examination revealed epidermotropism in 2 cases, a dermal infiltrate in all 3 cases, and subcutaneous involvement in 1 case. Immunohistochemical studies showed the presence of CD3(+) TCR delta(+) in 3 patients, CD8(+) in 1, and CD4(+), CD20(+), CD56(+), and beta F1(+) in none. All 3 cases exhibited an activated cytotoxic T-cell phenotype positive for T-cell intracellular antigen 1, perforin, and granzyme B. A clonal T-cell receptor gamma chain gene rearrangement was detected in all 3 cases by polymerase chain reaction. In situ hybridization was negative for EBV sequences in all 3 cases. Conclusion: gamma delta Cutaneous T-cell lymphomas are EBV-negative lymphomas that express a mature cytotoxic phenotype and have an aggressive clinical behavior.