A case of intra-osseous carcinoma of the mandible, suspected to arise from an odontogenic cyst

This is a case report of a patient with an intraosseous carcinoma of the mandible. The patient was a 49-year-old female with a chief complaint of right mandibular angle swelling. The right retromolar pad was tender and slightly swollen, whereas the overlying mucosa was intact. The orthopantomograph revealed an impacted wisdom tooth with an associated pericoronal radiolucency. The clinical diagnosis was an odontogenic cyst. The impacted wisdom tooth was therefore removed and marsupialization was performed. The histological diagnosis was an infected dentigerous cyst. Three months later, her right mandibule became swollen again. The histological diagnosis was hyperplasia of the lining epithelium with severe dysplasia. However, this time we hiopsied the deep sites of the cavity, and obtained a pathological diagnosis of squamous cell carcinoma.These results indicated that the lesion was an intra-osseous squamous cell carcinoma arising from an odontogenic cyst.