Methotrexate-associated Angioimmunoblastic T-cell Lymphoma Presenting with Acute Kidney Injury.

A man in his 60s on methotrexate for rheumatoid arthritis developed a fever and lymph node swelling, suggesting a lymphoproliferative disorder. Methotrexate was discontinued; however, the patient was admitted for acute kidney injury (AKI) and thrombocytopenia. Blood tests showed high levels of inflammatory markers, positive plasma Epstein-Barr virus DNA, and CD10-positive abnormal T cells, indicating T-cell neoplasm. CHOP chemotherapy with continuous hemodiafiltration improved the patient's condition. A lymph node biopsy confirmed the diagnosis of angioimmunoblastic T-cell lymphoma (AITL). To our knowledge, this is the first reported case of methotrexate-associated AITL complicated by AKI with a successful treatment course.