Imaging features of epidermoid cyst located in the floor of the mouth: case report and narrative review of literature.

Epidermoid cysts are benign slow-growing developmental lesions resulting from ectoder-mal tissue that can localise anywhere in the body. Only 7% of all epidermoid cysts are located in the head and neck area and, together with dermoid cysts, account for less than 0.01% of all oral cavity cysts. Herein, we present the case of a 17-year-old male diagnosed with a sublingual epidermoid cyst and a review of the literature on this rare localisation, focusing on clinical and imaging features, management and outcomes. All the articles re-porting epidermoid cysts located in oral cavity were searched using PubMed/Medline, dis-carding all those not located in head and neck district, not mentioning diagnostic imaging, not defined as epidermoid cysts by a histopathological diagnosis, and those for which only an abstract was available. In literature there were 35 articles, from 1993 to 2020, that meet the aforementioned requirements, for a total of 38 patients and 39 cysts. For each article, age, sex, onset time of symptoms, location, size and surgical access were analysed. Particu-lar attention was paid to the radiological investigation used in order to understand the most common imaging aspects and also rare cases with unusual presentations.