A retrospective study of the malignant change of odontogenic keratocyst.

The odontogenic keratocyst (OKC) is a common cystic lesion of the maxilla and mandible. Squamous cell carcinoma (SCC) arising from OKC or dysplasia occurring in OKC is rare. This study aimed to explore the incidence and clinical features of the dysplasia and malignant transformation of OKC. In this study, 544 patients diagnosed with OKC were collected. Among them, 3 patients were diagnosed as SCC arising from OKC, and 12 patients were diagnosed as OKC with dysplasia. The incidence was calculated. Clinical features were analyzed by chi-square test. In addition, a representative case reconstructing mandible with vascularized fibula flap under general anesthesia was reported. And cases reported before were reviewed. The incidence of the dysplasia and malignant transformation of OKC, which are highly associated with the clinical features of swelling and chronic inflammation, is about 2.76%. But the relevance between the dysplasia and malignant transformation and age, gender together with pain is not statistically high. All in all, the clinical features of swelling and chronic inflammation can be considered as characteristics of the dysplasia and malignant transformation of OKC. Although the pain isn't statistically relevant, it may be a dangerous clew. Also, combined with earlier literatures, the dysplasia and malignant transformation of OKC shows unique features of radiographs and histopathology.