Primary intraosseous mucoepidermoid carcinoma (PIOC) or Central Mucoepidermoid Carcinoma (CMC) of the jaw bones is an extremely rare malignant salivary gland tumor, comprising 2-3% of all mucoepidermoid carcinomas reported. We report a rare case of a 55 year-old female patient with advanced low-grade primary intraosseous mucoepidermoid carcinoma of the mandible. The patient was referred with a chief complaint of slowly progressive painless swelling in right cheek region for 2 years. On physical examination, a stony hard swelling was found, measuring 47x46x33 mm, fixed to the right posterior mandible and extending to the parotid region. Oral cavity examination showed an induration of the oral mucosa with poor state of dental health. No palpable lymph node was noticed in the neck on extraoral examination. Computed tomography (CT) with three-dimensional (3D) reconstruction (A,B,C,D) showed an agressive lytic process of the right mandibular ramus, with heterogeneous tissue density, blowing the cortical, having clear polycylic contours and extending into the surrounding soft parts without invading them. The patient underwent tumoral biopsy. Histopathological and immunohistochemical examination confirmed the diagnosis of a low-grade mucoepidermoïd carcinoma (MEC). Surgery is the treatment of choice, as mucoepidermoid carcinoma is considered globally resistant to radiotherapy and chemotherapy. Due to the advanced stage of the disease, the tumor was unresectable. The next best treatment option planned was exclusive conformal radiation therapy.

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Corresponding author
Zinah Idrissi Kaitouni, University Teaching Hospital Mohamed VI, Hematology and Oncology Hospital, Radiation Oncology Department, Marrakesh, Morocco (zinah.idrissikaitouni@gmail.com)