A Rare Presentation of Follicular Odontogenic Keratocyst of Maxillary Sinus Mimicking Dentigerous Cyst: A Case Report with 3-Year- Follow-Up.

Follicular keratocyst is a rare variant of odontogenic keratocyst (OKC), which surrounds the neck of an impacted tooth resembling a dentigerous cyst, usually diagnosed through radiographic and histological investigations. A 22-year-old female patient presented with pain in the right maxilla for the past 3 years. Intraoral examination revealed a missing right maxillary third molar. Computed tomography (CT) showed a well-defined hyperdense area in the right maxillary sinus involving the crown of an impacted right maxillary third molar within the cystic lesion. A provisional diagnosis of dentigerous cyst was made. The cystic lesion was then surgically enucleated with an impacted right maxillary third molar under general anesthesia. Histological investigation of the enucleated lesion was suggestive of a follicular keratocyst. No adverse effects or recurrence were elicited postoperatively at the 3-year follow-up. OKC, in relation to the third molar, clinically may represent any other odontogenic cysts. Histopathological examination remains the gold standard for assessing the final diagnosis and guides the selection of a definitive treatment modality.