The odontogenic keratocyst: orthokeratinized variant.

The histopathologic and clinical features of sixty cases of orthokeratinized odontogenic cysts were compared with those of odontogenic keratocysts (typically parakeratinized). According to the results of this study, the orthokeratinized odontogenic cyst appears to be a distinct clinicopathologic entity. This cyst is histologically characterized by a thin, uniform, epithelial lining with orthokeratinization and a subjacent granular cell layer. The basal cells are usually cuboidal or flattened. Clinically, the orthokeratinized cyst is a single cyst, shows a predilection for males, and is most often found in the second to the fifth decade, it appears most commonly as a dentigerous cyst in the posterior mandible. The orthokeratinized cyst shows little clinical aggressiveness. Follow-up of twenty-four patients revealed only one recurrence; of nineteen patients evaluated, none had features of the basal cell nevus-bifid rib syndrome. It is suggested that this cyst be called odontogenic keratocyst, orthokeratinized variant.