We recently reported two cases of reversible Epstein-Barr virus (EBV)-associated lymphomas in patients undergoing methotrexate therapy for rheumatic disease. The current study was undertaken to investigate how frequently lymphoid neoplasms in patients with rheumatic disease show features of lymphoproliferations occurring in immunocompromised patients. Eighteen patients (including the two previously reported patients) with rheumatoid arthritis or dermatomyositis who developed lymphoproliferative lesions and on whom detailed clinical information was available were studied. As a group these patients developed a spectrum of lymphoproliferative lesions; however, a subset of patients developed neoplasms with features associated with immunosuppression. The neoplasms occurred in extranodal sites in 10 (56%) patients, showed a diffuse large-cell histology in nine (50%) patients, and contained EBV (EBER1) transcripts and EBV latent membrane protein in six (33%) patients. In three (17%) patients the neoplasms showed the entire constellation of features typical of immunosuppression-associated lymphoproliferations, including extranodal location, large-cell or polymorphous histology, geographic areas of necrosis, and the presence of EBV. These three patients were receiving both steroids and methotrexate at the time they developed their neoplasms. The findings of this study support the hypothesis that a subset of lymphoid neoplasms in rheumatic patients occurs in an immunocompromised setting and suggest that therapeutic immunosuppression may contribute, at least in part, to the development of these lymphoid neoplasms.