Benign fibro-osseous lesions (BFOLs) are a particularly challenging set of diagnoses for the pathologist. This diverse collection of diseases includes fibrous dysplasia, ossifying fibroma and cemento-osseous dysplasia. While all three conditions have similar microscopic presentations, their treatment and prognosis differ, demanding an accurate and definitive diagnosis. A practical and systematic approach considering the patient's history, demographics, intraoperative presentation, and gross appearance with an emphasis on radiology and histology will be discussed.

Ameloblastomas are benign but aggressive odontogenic tumors that most commonly affect the posterior mandible. Approximately 15% occur in the maxilla, with a subset thought to originate from the epithelial lining of the sinonasal cavities. Histologically, sinonasal ameloblastomas are identical to those of the oral cavity, with classical features of palisaded columnar basilar cells surrounding a central proliferation that resembles the stellate reticulum of a developing tooth. Unlike the gnathic variant, sinonasal ameloblastomas tend to affect males more than females, and the incidence of diagnosis peaks at a later age, approximately 60 years old. The overall prognosis is favorable, with local recurrence being the most common long-term sequalae.