Epstein-Barr Virus Positive Mucocutaneous Ulcer Presenting in the Oral Cavity: A Rare Entity for Maxillofacial Surgeons

Epstein-Barr virus–positive mucocutaneous ulcer (EBVMCU) represents a rare, indolent B-cell lymphoproliferative disorder predominantly affecting elderly or immunocompromised patients. Its clinicopathological resemblance to aggressive lymphomas, including diffuse large B-cell lymphoma and classic Hodgkin lymphoma, necessitates meticulous diagnostic evaluation to prevent unnecessary cytotoxic therapy. We report an 80-year-old female presenting with a painful ulcer in the left retromolar trigone. Her history included bisphosphonate use for osteoporosis without documented immunosuppression. Initial suspicion favored odontogenic infection; however, incisional biopsy at tooth extraction revealed EBV-positive large B-cells, establishing EBVMCU. Imaging demonstrated localized disease. Given persistent ulceration and absence of reversible immunosuppressive factors, rituximab (anti-CD20) monotherapy was administered, achieving marked regression and complete mucosal healing within six months. This case underscores immunosenescence as a likely predisposing factor and highlights the necessity of comprehensive histopathological and immunohistochemical assessment to differentiate EBVMCU from malignant lymphoproliferative entities. While frequently self-limiting, persistent disease may warrant targeted anti-CD20 therapy.