Orthokeratinized odontogenic cysts are developmental cysts that occur in the jaw that account for approximately 7%–17% of all cysts in the jaws. Studies have shown that malignant transformation of odontogenic cysts most often occurs in inflammatory cysts, such as periapical cysts, but malignant transformation of orthokeratinized odontogenic cysts has also been reported. In this report, we present an uncommon case of squamous cell carcinoma arising from an orthokeratinized odontogenic cyst.

Orthokeratienized odontogenic cyst (OOC) is a comparatively unusual developmental odontogenic cyst arising from odontogenic epithelium. Recurrence has rarely been noted, and has been reported in less than 2% of cases. Epidermoid cyst (EDC) is a benign cystic lesion, which is lined by stratified squamous epithelium and includes keratin debris. They can present anywhere in the body but are rare in the head and neck areas. In this report, we present an uncommon case of simultaneous occurrence of OOC in mandible and EDC around the areas of both ears in a patient who has no history of genetic syndrome.