A 75-year-old Japanese woman with a 20-year history of rheumatoid arthritis presented with symptomatic bilateral pleural effusion and lung and brain tumors. She had received methotrexate for five years and tacrolimus for one year. A brain biopsy specimen showed the pathological features of lymphoproliferative disease, but a bone marrow biopsy showed proliferation of plasma cells. She was finally diagnosed with coexistent lymphomatoid granulomatosis (LYG) of the brain and lung and multiple myeloma (MM) of the bone marrow and received chemotherapy for both. This report shows that immunodeficient patients are at risk of developing the unusual coexistence of LYG and MM.
Keywords: lymphomatoid granulomatosis; methotrexate; multiple myeloma; rheumatoid arthritis; tacrolimus.