Primary intraosseous mucoepidermoid carcinoma of the mandible: radiographic evolution and clinicopathological features.

Mucoepidermoid carcinoma (MEC) can be rarely found as a primarily intraosseous lesion and mistaken for other intraosseous or odontogenic pathology. A 65-year-old man had a poorly defined radiolucency distal to the left mandibular second molar root. Periapical radiographs demonstrated a minor radiolucency from 2.5 years prior. An oral and maxillofacial surgeon felt the radiolucency represented periodontal disease, extracting tooth #18. The differential diagnosis of mixed radiolucent/radio-opaque mandibular lesions includes: (1) fibro-osseous lesion, (2) odontogenic and non-odontogenic cyst, (3) infection and inflammatory lesion, or (4) benign or malignant neoplasm (odontogenic, non-odontogenic, or metastatic). Histological analysis revealed low-grade MEC. A composite resection was performed with a 1 cm margin from first molar to ascending ramus. A buccal fat pad advancement flap covered the defect with an iliac crest bone graft placed later for a resulting osseous defect. Careful examination and diagnostic work-up for odontogenic cysts should be provided as they may harbour malignant tumours.