Anterior Maxillary Odontogenic Keratocyst Mimicking an Infected Radicular Cyst: A Case Report

Odontogenic keratocyst (OKC) is a developmental odontogenic cyst known for its aggressive behavior, characteristic histology, and high recurrence rate.It is typically lined by parakeratinized epithelium, while a purely orthokeratinized lining is now recognized as a separate entity, the orthokeratinized odontogenic cyst (OOC).Lesions showing both types of keratinization are rare and can pose diagnostic and management challenges.We report a 38-year-old man with no relevant medical history who presented with a six-month history of continuous, dull pain in the upper left anterior region, aggravated by mastication and radiating to the head.Clinical examination showed tenderness on percussion in teeth 21 to 25.An orthopantomogram (OPG) revealed a well-defined cystic radiolucency extending from 21 to 25. Aspiration cytology suggested an infected radicular cyst.After endodontic treatment of the involved teeth, the lesion was enucleated with apicectomy of 21, 22, and 23.Histopathology of the specimen revealed a cyst lined by keratinized stratified epithelium five to six cells thick, with a palisaded, hyperchromatic basal layer and daughter cysts in the connective tissue wall, as well as both orthokeratinized and parakeratinized areas, consistent with a mixed variant of OKC.Subsequently, the cavity was reopened, topical 5-fluorouracil (5-FU) was applied, and periodic iodoform-paraffin gauze packing was performed.The patient remains under follow-up.This case underlines that OKC can mimic inflammatory cysts, that final histopathology is essential, and that the mixed variant needs careful distinction from the OOC because their behavior and management differ.