Hamadan University of Medical Sciences Avicenna Journal of Dental Research 2423-7582 15 4 2023 12 29 Intraosseous Mucoepidermoid Carcinoma of the Mandible Arising From a Cystic Lesion: A Case Report 178 182 10.34172/ajdr.1721 EN Mohammad Reza Jamalpour https://orcid.org/0000-0002-0092-0443 Arash Dehghan Reza Nadripour Faryad Fatehi Hossein Nahidfar Hamid Naderi https://orcid.org/0000-0001-6936-5686 Journal Article 10.34172/ajdr.1721 2023 04 06 2023 05 06 Mucoepidermoid carcinoma (MEC) can be found as a primary intraosseous lesion, accounting for 2-3% of head and neck MEC. The mandibular premolar-molar region is the most common site, up to 50% of which is associated with dental cysts and/or impacted teeth. Histopathologically, it is classified into low, intermediate, and high grades. The best modality of treatment for intraosseous MEC is radical surgical resection. Radiotherapy is recommended to improve the prognosis in patients with positive margins, positive node disease, and moderate- and high-grade lesions. This paper reports a rare case of intraosseous MEC of the mandible in a 17-year-old female, discovered after the panoramic radiography of the jaws and treated by the segmental resection of the mandible through transoral approach and adjuvant radiotherapy.