Odontogenic Keratocysts: A Clinicopathological Study in Hong Kong Chinese


  • K. Y. Lam FRCPA,

    Corresponding author
    1. Department of Pathology, University of Hong Kong, Queen Mary Hospital, Hong Kong, China
    • Dr. K. Y. Lam, Department of Pathology, University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong, Hong Kong SAR.
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  • Alexander C. L. Chan FRCPA

    1. Department of Pathology, Queen Elizabeth Hospital, Hong Kong, China
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Objective 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.