Orthokeratinised odontogenic cyst of the anterior mandible: A case report

The orthokeratinized odontogenic cyst (OOC) is a rare developmental odontogenic cyst of the jaws, which is lined by stratified squamous epithelium. These slowly growing cysts are painless and often detected incidentally during radiographic investigations. The OOC occurs over a broad age range, with a predilection for the third and fourth decades of life. Previous studies have reported that the OOC occurs more frequently in male patients. The molar and ramus regions of the mandible are the more commonly involved sites. The radiographic features of periapical OOCs are similar to those of other unilocular cysts and are difficult to differentiate. The prognosis after enucleation is very good, with a low recurrence rate. Here, we describe an uncommon case of an OOC located in the anterior mandible. The patient was a 16-year-old adolescent, who was referred to our department for further evaluation of a radiolucent periapical lesion in the anterior mandible. Based on clinical findings, a biopsy was performed for a tentative diagnosis. With the patient under general anesthesia, the cyst was subsequently resected. Histologically, the cyst wall was lined by keratinizing stratified squamous epithelium and included a granular cell layer. The cystic lumen was filled with laminated keratin debris. The findings were diagnosed as an OOC. No recurrences or postoperative complications have been noted over a 42-month period. Although the occurrence of OOC in the anterior mandible is rare, it should be included in the differential diagnosis along with other radiolucent lesions of the jaw.