ビスフォスフォネートによる上顎骨壊死とメトトレキサート関連リンパ増殖性疾患の併発を疑った1例

抄録

Recently, bisphosphonate-related osteonecrosis of the jaw （BRONJ） is a very severe problem. Although methotrexate （MTX） has been used as standard therapy for patients with rheumatoid arthritis （RA）, MTX-associated lymphoproliferative disorder （MTX-LPD） has been reported recently. We report a suspected case of both BRONJ and MTX-LPD. A 66-year-old woman with osteoporosis and RA was referred to our department for pain after extraction of the right maxillary first molar. MTX and alendronate had been administered to the patient. CT revealed extensive osteonecrosis of the maxilla. The patient was given a diagnosis of BRONJ. Although minimally invasive treatment was performed, the osteonecrosis gradually enlarged. A biopsy of the mucosa of the hard palate was performed to check for tumorous lesions. The atypical cells were positive for CD20, CD30, multiple myeloma oncogene 1 （MUM1）, and EBV-encoded small RNAs-in situ hybridization （EBER-ISH）, and negative for CD15. The pathological diagnosis was diffuse large B-cell lymphoma. Finally, the lesion was diagnosed as MTX-associated LPD （MTX-LPD） in consideration of treatment with MTX. After discontinuation of MTX, the lesion gradually disappeared.