Fatal subcutaneous panniculitis-like T-cell lymphoma gamma/delta subtype (cutaneous gamma/delta T-cell lymphoma): report of a case and review of the literature.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a distinct type of peripheral T-cell lymphoma, which has gained recognition over the past decade. The disease presents complex clinical, pathologic, and immunohistochemical features, which warrant awareness by dermatologists, dermatopathologists, hematopathologists, hematologists, oncologists, and internists. SPTCL was initially included as a provisional entity in the Revised European-American Lymphoma classification, followed by the European Organization for Research and Treatment of Cancer classification as a primary cutaneous lymphoma, and subsequently as a distinct entity by the World Health Organization classification. It is known that patients diagnosed with SPTCL usually respond poorly to therapy, and the tumor progresses aggressively. Data from recent studies in a series of cases of SPTCL by the European Organization for Research and Treatment of Cancer Cutaneous Lymphoma Group have further identified SPTCL as a heterogeneous disease entity, which comprises an alpha/beta subtype (SPTCL-AB) and a gamma/delta subtype (SPTCL-GD). The latter has recently been included in the entity of "cutaneous gamma/delta T-cell lymphoma" by the World Health Organization, Pathology and Genetics of Skin Tumours. The clinical, histologic, and immunophenotypic data, treatment, and prognosis, appear different in the 2 subtypes of SPTCL. We report a case of fatal SPTCL-GD (cutaneous gamma/delta T-cell lymphoma), with detailed clinicopathologic features, immunohistochemical studies, treatment, and clinical course. In view of its aggressive behavior, identification of this disease is critical for proper management and treatment.