Intraosseous Mucoepidermoid Carcinoma Mimicking an Odontogenic Cyst: A Case Report

Introduction Intraosseous mucoepidermoid carcinoma (IMEC) is a rare salivary gland malignancy arising within the jaws. Its clinical and radiographic resemblance to odontogenic cysts can delay diagnosis and presents an important diagnostic challenge for dental practitioners. Objectives To describe the diagnosis and multidisciplinary management of a mandibular IMEC initially considered to represent an odontogenic cyst, and to highlight its key clinical learning points. Methods The clinical presentation, imaging, histopathology, molecular investigations, treatment and postoperative follow-up were reviewed. The diagnosis was assessed against established criteria for primary intraosseous mucoepidermoid carcinoma and the relevant literature. Results A 51-year-old woman presented with a radiolucent lesion in the posterior mandible at the site of a previous third molar extraction. Initial histopathological assessment suggested an inflamed dentigerous cyst with atypical features. Specialist review demonstrated low-grade mucoepidermoid carcinoma, and fluorescence in situ hybridisation confirmed a MAML2 rearrangement. Following multidisciplinary discussion, the patient underwent marginal mandibulectomy with preservation of mandibular continuity and histologically clear margins. At 12-month clinical review, there was no evidence of local or regional recurrence; at approximately 15 months, CBCT demonstrated postsurgical change without definite evidence of recurrent disease. Conclusions IMEC should be considered when the clinical, radiological and histopathological features of an apparent odontogenic cyst are discordant. Careful tissue assessment, specialist pathological review and molecular testing may be decisive in establishing the diagnosis. Management should be individualised through multidisciplinary review, with complete surgical excision and continued long-term surveillance.