Unusual presentation of ameloblastoma and a review of its biological behaviour

Ameloblastoma is a benign odontogenic tumour occurring primarily in the mandible with rare occurrence outside the jaw. We report a case of an ameloblastoma presenting as a polypoidal mass in the right nasal cavity of a 72-year-old woman. She presented with progressive nasal blockage symptoms and examination revealed a mass occupying the right nostril. Initial tissue biopsy confirmed conventional ameloblastoma. Subsequent imaging study showed a mass involving the right maxilla. Primary tumour from the maxilla extending into the sinonasal tract was favoured over a much rarer primary ameloblastoma of the sinonasal tract, in view of the tumour bulk in the maxilla. Unfortunately, the patient defaulted her follow-up. Ameloblastomas are known to recur locally thus excision with clear margins is paramount. Recurrence is also influenced by factors such as the presence of B-Raf proto-oncogene (BRAF) and Smoothened, frizzled class receptor (SMO) genetic mutations, with SMO mutation found to be associated with maxillary location in the older age group. Ameloblastomas can metastasise without undergoing malignant cytological changes, with mandibular tumours being far more likely to do so. Long-term follow-up and regular computed tomography (CT) monitoring is required post excision.