A Case of Epidermal Cyst of the Floor of the Mouth Misdiagnosed as a Plunging Ranula

Epidermal cysts are generally benign tumors that usually originate from the skin caused by inflammation of hair cortex and proliferation of epidermal cells within the dermis. Epidermoid cysts are often found on the head, neck, back, or genitals; in contrast, for these cysts to occur in mouth floor are rare. We recently encountered a 14-year-old female with a mass in submental area, which was finally diagnosed as epidermal cyst after an initial misdiagnosis as plunging ranula. We report this rare, unique case with literature review.