Lymphomatous polyarthritis in patients with peripheral T-cell lymphoma

Direct involvement of the joints is a rare complication of malignant lymphoma and lymphoma cells in synovium or synovial fluid have been characterized in only a very few cases. We report two cases of CD4-positive, HTLV-I-negative peripheral T-cell lymphomas that manifested polyarthritis infiltrated with lymphoma cells which we further characterized. Patient 1, with a prior 7-year history of cutaneous T-cell lymphoma (mycosis fungoides) and polyarthralgia, developed pain and swelling in the right knee joint and right femoral region. Patient 2 was initially diagnosed with immunoblastic lymphadenopathy, later rediagnosed as the prodromal stage of T zone lymphoma. Seven years later she developed skin eruptions, cervical lymph node swelling, polyarthritis, and pleural effusion. Synovial fluid analysis in both cases showed predominant CD3+ or cytoplasmic CD3+, CD4+, and CD8- atypical lymphoid cell infiltration. In both cases the T-cell receptor beta and gamma chains were rearranged in the synovial fluid mononuclear cells. Analysis of these two cases and a review of the literature suggest that lymphoma cell infiltration of synovium occurs preferentially in patients with CD4+ peripheral T-cell lymphoma.