Lymphoproliferative disorder progressing after partial remission following immunosuppressive drugs withdrawal in a patient with rheumatoid arthritis.

Lymphoproliferative disorders (LPDs) are serious complications that arise in patients with rheumatoid arthritis (RA) receiving immunosuppressive drugs (ISDs). Here, we reported a 73-year-old woman diagnosed with RA at 60 years of age and treated with methotrexate, bucillamine, prednisolone, and infliximab. She was referred to our hospital, Osaka Metropolitan University Hospital, with general malaise, pancytopenia, a right adrenal mass, and enlarged periaortic lymph nodes. Epstein-Barr virus was detected in serum. We suspected LPD development and performed a bone marrow biopsy, on which no malignant cells could be detected. Upon ISDs withdrawal, her symptoms and blood counts improved, and the right adrenal mass and enlarged lymph nodes regressed. The patient was followed up for clinical LPD. However, 7 months after the initial visit to our hospital, she developed fever and pancytopenia. A repeat bone marrow biopsy confirmed the diagnosis of Epstein-Barr virus-positive diffuse large B-cell lymphoma complicated by haemophagocytic syndrome. After pulse steroid therapy, the patient received rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone therapy, which resulted in a complete response. In conclusion, when LPDs develop in patients with RA during ISD treatment, LPDs can progress and complicate haemophagocytic syndrome after partial remission following ISDs withdrawal. Therefore, we should carefully follow up RA patients with LPDs, and aim to achieve an early diagnosis of LPD and promptly initiate chemotherapy.