Methotrexate-associated lymphoproliferative disorder in the stomach and duodenum: a case report

BACKGROUND: Methotrexate-associated lymphoproliferative disorder (MTX-LPD) can present as a benign lymphoid proliferation or a malignant lymphoma in patients taking MTX. Almost 50% of MTX-LPD cases show spontaneous remission after withdrawal of MTX treatment. Studies have suggested that the hyper-immune state of rheumatoid arthritis, the immunosuppressive state associated with MTX, and the carcinogenicity of the Epstein-Barr virus might contribute to MTX-LPD development. Although most cases of MTX-LPD occur at extranodal sites, few cases of MTX-LPD affecting the stomach and duodenum have been reported. To our knowledge, no other study has reported on the endoscopic observations of dramatic withdrawal and appearance of multiple digestive tract lesions in a short period of time. Herein, we report the clinical course and imaging findings of our case, which may be useful for understanding the pathological condition of MTX-LPD. CASE PRESENTATION: We describe the case of a 70-year-old woman with MTX-LPD of the stomach and duodenum. Disease regression was temporarily achieved after cessation of MTX treatment; however, it subsequently recurred, and complete response was only achieved after six cycles of rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisolone (R-CHOP) chemotherapy. CONCLUSIONS: The first-choice therapy for patients taking MTX who develop suspected MTX-LPD should be the withdrawal of MTX treatment. Even after remission is achieved, patients should be kept under careful observation, and if the disease recurs, chemotherapy should be commenced promptly.