Orthokeratinized Odontogenic Cyst: An Unusual Histopathological Presentation

Introduction: The orthokeratinized odontogenic cyst (OOC) is an uncommon developmental cyst that occurs between the second to fifth decades, more commonly in males. It is a solitary lesion that mostly occurs in the mandible rather than the maxilla. Histologic features include a thin, uniform epithelial lining with orthokeratinization and a prominent granular layer below a noncorrugated onion-skin-like surface. Case Presentation: A ۴۰-year-old man presented with pain and swelling in the left mandibular canine molar area. The panoramic radiograph revealed a well-defined radiolucency extending from the left mandibular canine to the left mandibular molar, with scalloped projections between the teeth roots. Microscopic examination showed a cystic lesion lined by an orthokeratinized stratified squamous epithelium, and a prominent granular layer beneath the cornified layer was seen. The features were those of an OCC. Conclusions: From the demographic and radiographic perspectives, the features of OOCs can be similar, but more variation can be found on routine histopathological analyses.