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 ectodermal 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 reporting epidermoid cysts located in oral cavity were searched using PubMed/Medline, discarding 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. Particular attention was paid to the radiological investigation used in order to understand the most common imaging aspects and also rare cases with unusual presentations.