[Two cases of subcutaneous panniculitis-like T-cell lymphoma (CD4- CD8+ CD56-)].

BACKGROUND: Subcutaneous T-cell lymphoma is a rare disease and diagnosis is often difficult. We report two cases of subcutaneous T-cell lymphoma simulating panniculitis and initially treated with systemic steroids. PATIENTS AND METHODS: Case No. 1. A 75-year-old woman, otherwise asymptomatic, presented with plaques and nodules of the legs present for 4 months. Histological and immunohistochemical analysis revealed subcutaneous T-cell lymphoma of CD4- CD8+ CD56- phenotype. Improvement was observed with systemic steroids followed by radiotherapy. Case No. 2. A 53-year-old woman presented with a 10-year history of recurrent infiltrated plaques. Lupus panniculitis was evoked but not confirmed. In the context of new panniculitis lesions, histological examination showed a dense lymphocytic infiltrate involving the fat lobules. Lymphocyte immunophenotyping and genotyping led to a diagnosis of subcutaneous T-cell lymphoma of CD4- CD8+ CD56- phenotype. Molecular analysis showed T-cell monoclonality (alpha beta). The lesions improved after few months of systemic corticosteroids. Although new nodular lesions appeared from time to time, further therapy was not deemed necessary. DISCUSSION: A distinction is currently made between two types of subcutaneous T-cell lymphomas and the prognosis and therapeutic consequences differ widely. In our two patients, subcutaneous CD8+ T-cell lymphoma was diagnosed. The clinical course was indolent in both cases. Differential diagnosis with regard to lupus panniculitis can be difficult because of its slow progression. In such cases of low-grade lymphomas, first-line therapy may be limited to systemic corticosteroids.