Primary juxtaarticular soft tissue lymphoma arising in the vicinity of inflamed joints in patients with rheumatoid arthritis

Aims: Primary soft tissue lymphoma is uncommon and little is known regardin g its aetiology and pathogenesis. In a review of 37 soft tissue lymphomas w e uncovered three cases associated with rheumatoid arthritis which we repor t herein. Methods and results: The clinical records and pathology of the cases are de scribed together with the results of in situ hybridization studies with oli gonucleotide probes to Epstein-Barr virus (EBV) encoded RNA (EBER), All thr ee patients were females with a long-standing history of rheumatoid arthrit is ranging from 9 to 17 years, Each presented with a soft tissue mass in th e vicinity of a joint affected by rheumatoid disease. All had received prio r treatment with nonsteroidal anti-inflammatory drugs and one also received gold, penicillamine and intra-articular steroids to affected joints. None had received methotrexate. Histologically, the juxtaarticular soft tissue m asses were all B-cell lymphomas. None were associated with EBV as determine d by in situ hybridization. Conclusions: These cases document an association between rheumatoid arthrit is and soft tissue lymphoma of B-cell type, arising in the vicinity of an a ffected joint. Chronic local immune stimulation may have played a significa nt role in the genesis of these lymphomas, unlike the frequently reversible and EBV-positive lymphomas that occur in rheumatoid patients on immunosupp ressive therapy.