Successful treatment of immunodeficiency-associated EBV-negative lymphoproliferative disorders in rheumatoid arthritis by methotrexate withdrawal and prevention of its relapse by rituximab administration.

Immunodeficiency-associated lymphoproliferative disorders (LPD) in rheumatoid arthritis are a rare, aggressive, and life-threatening clinical entity. We describe a 60-year-old man who had rheumatoid arthritis that was treated with methotrexate. Eight months after the treatment, the case was diagnosed as Epstein-Barr virus-negative LPD (diffuse large B-cell lymphoma) with abdominal bulky mass and clinical stage IVB at high risk in the international prognostic index. Immediate withdrawal of methotrexate led the patient to achieve complete remission, and 8 subsequent courses of rituximab treatment for the prevention of relapse kept the patient disease-free for 29 months. Our case suggests that these treatments may be an effective, safe, and feasible strategy for immunodeficiency-associated LPD in rheumatoid arthritis.