Orthokeratinized odontogenic cyst associated with multinucleated giant cell reaction: report of unusual findings

ABSTRACT Orthokeratinized odontogenic cysts are developmental odontogenic cysts, presenting with low frequency, low rate of recurrence and their ethiopathogenesis is unknown. Radiographically, they show a radiolucent area in the mandibular posterior region. The aim of this report is to describe an unusual case of orthokeratinized odontogenic cysts, radiographically exhibiting radiopaque areas with an aspect of calcifications in the lesion. Based on this, the clinical hypothesis of ameloblastic fibro-odontoma was suggested. After incisional biopsy and microscopic analysis, the conclusive diagnosis was orthokeratinized odontogenic cysts. The radiopaque foci were observed to be associated with a foreign body reaction. The patient was submitted to surgery under local anesthesia, with intraoral access for complete excision of the lesion and to re-establish esthetics. After follow-up of 24 months there were no signs of recurrence. Knowledge of this type of reaction is important because of the risk that the lesion may mimic a potentially more aggressive lesion, affecting the choice of treatment.