Subcutaneous panniculitis-like T-cell lymphoma:new concept in WHO-EORTC classification forcutaneous lymphomas

Objective: To investigate the clinicopathologic features, immunophenotype, cell derivation and prognosis of subcutaneous panniculitis-like T-cell lymphoma (SPTL). Methods: According to the new WHO-EORTC classification for cutaneous lymphomas, clinical data, histological features and immunohistochemistry of six SPTL cases were studied. Six paraffin-embedded specimens and one frozen specimen were marked with betaF1, respectively. Results: Among six patients with median age of 25.5, two were males and four were females. They usually presented with painless nodules and/or plaques. A few had fever, anemia and splenomegaly. Neoplastic cells were mainly limited to the subcutaneous tissue with nuclear atypia and mitosis. Variable fat necrosis and cytophagocytosis were seen. Neoplastic cells were positive for betaF1, CD3, CD8, TIA-1, GB, LCA and CD45RO but negative for CD4, CD30, CD56, CD20 and CD79a. All six patients got complete remission with a median follow-up of 37 months, and only one died of diabetes mellitus, hypertension and heart failure 42 months after the diagnosis. Conclusions: SPTL is a rare cytotoxic T-cell lymphoma derived from alpha/beta T cell, which has a protracted clinical course with a 5-year survival rate of over 80% of patients. Complete immunochemical studies are essential for the correct diagnosis of SPTL.