Odontogenic keratocysts: A clinicopathological study in Hong Kong Chinese

dObjective: To analyze the clinicopathological features of odontogenic keratocysts in Chinese patients. Study Design: Retrospective analysis. Methods: The clinical records and pathological features of odontogenic keratocysts from 69 ethnic Hong Kong Chinese patients (40 male and 29 female patients) were reviewed. Results: The male-to-female ratio was 1.4:1; patient age ranged from 6 to 69 years with a modal peak in the third decade (mean age, 28 y; median age, 23 y), The preoperative diagnosis was correct in 78% of the cases and the most common misdiagnosis was dentigerous cyst. Sixty-two percent of the cysts were found in the mandible, and 38% in the maxilla. Multiple cysts occurred in 9% (including three cases of basal cell nevus syndrome). Histologically, 82.6%, 5.8%, and 11.6% of the cysts were parakeratinized, orthokeratinized, and mixed types, respectively. Patients with multiple cysts all showed parakeratinization. The majority (80%) of the cysts were lined by epithelia with a thickness of five to eight cells. Surface corrugation, subepithelial split, suprabasal split, satellite microcysts, epithelial islands, significant inflammation, hyaline bodies, and dystrophic calcification were present in 100%, 81%, 25%, 38%, 42%, 46%, 7%, and 10% of cysts, respectively. The overall recurrence rate was 24%, with a median time for first recurrence of 19 months (range, 1 mo-22 y). Cysts showing orthokeratinization or mixed types of keratinization recurred less often than parakeratinized cysts. Recurrence had the same type of keratinization as the initial cyst. Conclusions: Pathological examination of keratocysts is important, because keratocysts have different clinicopathological features and carry a risk for clinical misdiagnosis.