Orthokeratinized Odontogenic Cyst

Orthokeratinized odontogenic cyst (OOC) is a relatively rare developmental cyst of odontogenic origin, accounting for approximately 1% of all odontogenic cysts. It predominantly occurs in the posterior region of the mandible, and literature reports suggest that OOC primarily affects individuals of white ethnicity aged 21–40 years. It is more common in males, with a ratio of incidence between males and females (2–2.59) to 1 [1–5]. OOC typically presents as an isolated, well-defined unilocular radiolucency in imaging examination, with approximately half of the cases exhibiting an association with an unerupted tooth. The cyst wall is composed entirely or predominantly of orthokeratinized stratified squamous epithelium in histology, accompanied by a prominent granular cell layer. No reports on the OOC related to the nevoid basal cell carcinoma syndrome have been found. Although OOC shares clinical and imaging similarities with odontogenic keratocyst (OKC), the differences in histological features and biological behavior could distinguish the two [4–8]. In accordance with literature reports, the recurrence rate of OOC was less than 2%. A close postoperative follow-up visit is still necessary.