Massive Mandibular Fibrous Dysplasia Mimicking Calcifying Epithelial Odontogenic Tumor Radiologically: A Case Report.

Fibrous dysplasia is a benign fibro-osseous lesion that may occasionally mimic odontogenic tumors radiologically. We report a rare case of a massive mandibular fibro-osseous lesion in a 58-year-old female presenting with progressively increasing lower facial swelling, trismus, and neck pain for four years. Contrast-enhanced computed tomography revealed a large (13 × 11 × 15 cm) expansile lytic lesion with dense calcified nodules, cortical thinning, and cortical breaches, radiologically suggestive of calcifying epithelial odontogenic tumor (Pindborg tumor). Initial biopsy demonstrated fibrocollagenous tissue with dead bone; however, due to the aggressive radiological appearance and extensive mandibular involvement, provisional diagnosis favored calcifying epithelial odontogenic tumor. The patient underwent subtotal mandibulectomy with reconstruction plate fixation, local flap reconstruction, and elective tracheostomy. Final histopathological examination revealed a fibro-osseous lesion with irregular immature bony trabeculae within fibrous stroma, consistent with fibrous dysplasia. Postoperatively, the patient was managed with regular oral cleaning, tracheostomy care, and speech and swallow therapy. This case highlights the diagnostic challenges associated with giant mandibular fibro-osseous lesions and emphasizes the importance of definitive histopathological evaluation.