Methotrexate-associated Intravascular Large B-cell Lymphoma in a Patient with Rheumatoid Arthritis

Intravascular large B-cell lymphoma (IVLBCL) is a rare and clinically aggressive lymphoma with an unfavorable prognosis. We report the case of a 50-year-old woman who was diagnosed with IVLBCL during treatment with methotrexate (MTX) and biologic agents for rheumatoid arthritis. The symptoms showed partial improvement only after the cessation of both treatments. She subsequently received chemotherapy and achieved a complete remission and has remained free of recurrence for 2 years without any further treatment. We herein describe a rare case of IVLBCL which presented with the features of an MTX-associated lymphoproliferative disorder.