[Oral Mucosal Diffuse Large B-cell Lymphoma Caused by Long-term Oral Methotrexate:Report of One Case].

A case of primary oral mucosal diffuse large B-cell lymphoma(DLBCL)due to long-term use of methotrexate(MTX)for the treatment of rheumatoid arthritis(RA)was admitted to the Department of Hematology,Fujian Medical University Union Hospital.We analyzed and discussed the clinical features,diagnosis and treatment,and prognosis of specific malignant lymphoma induced by MTX in this RA patient.Our purpose is to improve the awareness and knowledge of other iatrogenic immunodeficiency-associated lymphoproliferative disorders of clinicians and pathologists.This study provides a new reference for the clinical diagnosis and treatment of MTX-associated DLBCL.