Primary Cutaneous Gamma/Delta T-cell Lymphoma in Taiwan: A Series of Six Cases with Frequent Solitary Presentation and Relatively Indolent Behavior.

Background Primary cutaneous gamma/delta T-cell lymphoma is aggressive, frequently presenting as multiple plaques, tumors, and/or subcutaneous nodules. Methods In this study, we conducted a retrospective study in a tertiary center in Taiwan to characterize this rare tumor. Results We identified six patients. Five presented with a solitary lesion, including two with clinical impression of epidermal inclusion cyst or lipoma. Two of four evaluable cases exhibited epidermotropism, with one mimicking Pautrier's microabscess. The neoplastic cells were pleomorphic and mostly medium to large-sized. In all cases, the neoplastic cells expressed TCR-γ and/or TCR-δ, with four coexpressing βF1. Two of these βF1+ cases co-expressed TCR-γ, but not TCR-δ (two different clones). All were negative for EBV, low stage, and treated with radiotherapy alone or combined chemotherapy and radiotherapy. In two patients, lymphoma relapsed in 3 and 7 months, respectively, with one patient died of the disease in 7 months. Four other patients were free of disease for 6-126 months. Conclusion PCGD-TCL cases in Taiwan are more commonly solitary, frequently with indolent courses. The two currently available TCR-δ clones alone might be insufficient to detect all tumors. This article is protected by copyright. All rights reserved.