{Reference Type}: Case Reports {Title}: Epstein-Barr Virus-Positive Mucocutaneous Ulcer With Medication-Related Osteonecrosis of the Jaw Arising in the Mandible of a Rheumatoid Arthritis Patient: A Case Report. {Author}: Kanno NI;Ito T;Takaoka S;Yamagata K;Bukawa H; {Journal}: Cureus {Volume}: 16 {Issue}: 5 {Year}: 2024 May 暂无{DOI}: 10.7759/cureus.61280 {Abstract}: This study presents a rare case of an Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) co-existing with medication-related osteonecrosis of the jaw (MRONJ) in the mandible of a 54-year-old Japanese man who complained of painful swelling of the left mandibular gingiva over the past three months. The patient had a history of methotrexate (MTX) and bisphosphonates (BPs) use. Intraoral examination revealed a 35 mm large ulcerative lesion with marginal gingival swelling and bone exposure on the left side of the mandible. A biopsy was performed, confirming the diagnosis of EBVMCU with MRONJ. Due to the enlargement of the bone exposure, marginal resection of the mandible was performed under general anesthesia as a treatment for residual MRONJ. At the two-year follow-up, no evidence of recurrence was observed.