上顎歯肉に発生したメトトレキサート関連リンパ増殖性疾患の1例―本邦の口腔領域における発症例に関する文献的検討―

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Recently, the occurrence of methotrexate-associated lymphoproliferative disorders (MTX-LPD) in the oral area is reported one after another. We report a case of MTX-LPD of the maxillary gingiva associated with rheumatoid arthritis (RA). A 80-year-old man was referred to our clinic because of severe pain associated with a ulcer on the left side of the maxillary gingiva. On blood tests, soluble interleukin-2 receptor (sIL-2R) was high, and EBV infection was detected. The histopathological diagnosis was EBV-positive diffuse large B cell lymphoma (DLBCL). He had been receiving methotrexate for RA. We therefore requested discontinuation of methotrexate, and the lesion was decreased and symptoms disappeared. Examination after 21 months showed no evidence of recurrence.
We reviewed reports documenting 17 cases of oral MTX-LPD in Japan. The age of onset was 40-84 years old, the male-to-female ratio was 4:13, and the methotrexate treatment period was 1-114 months. The affected sites were the maxillary and mandibular gingiva in 14 cases, the tongue in 1 case, and the mouth floor in 1 case. On histopathological classification, 14 cases were non-Hodgkin’s lymphoma, and 1 case was Hodgkin's lymphoma. As for the course of treatment, 11 cases had remission with cessation of methotrexate. Symptoms improved in 1-2 weeks, and lesions disappeared in 1-4 months.