Calcifying odontogenic cyst with odontogenic keratocyst: a case report and review of the literature.

The calcifying odontogenic cyst (COC), first identified as a separate and distinct lesion by Gorlin et al. in 1962, is an uncommon benign lesion, consisting of a proliferation of odontogenic epithelium and scattered nests of ghost cells and calcifications that may form the lining of a cyst or present as a solid mass. The COC occurs alone or occasionally with odontomas or other odontogenic tumors, and it is this variable histology and clinical behavior that has raised the question of whether or not it is a cyst or a true neoplasm. The odontogenic keratocyst (OKC) is a locally aggressive odontogenic cyst lined by parakeratinizing epithelium that also exhibits characteristics of a neoplasm, including rapid growth, a high rate of recurrence when treated conservatively, and the presence of a gene mutation. We describe a patient diagnosed with an OKC of the mandible that arose simultaneously with a COC of the anterior maxilla. The occurrence of 2 "cystic neoplasms" in the same patient is an occurrence which to our knowledge has not been previously reported. We discuss the significance of the case and review the current literature regarding these lesions.