Epidermoid Cyst in the Submandibular Region Mimicking Plunging Ranula: A Case Report

Epidermoid cysts rarely present in the submandibular area, constituting approximately less than 7% of all cystic lesions in the head and neck region and less than 0.01% of all oral cavity cysts. Therefore, epidermoid cysts can be easily misdiagnosed, as the differential diagnosis for a submandibular area mass is very broad. Imaging can help define characteristics of the mass; however, a pathologic specimen is usually required for the final diagnosis. Surgical excision is often required and tolerated well by most patients. However, there is a risk of recurrence of the cyst after excision, as well as a rare chance for malignant transformation if not excised, which must be discussed with the patient at the time of diagnosis of epidermoid cyst. We present a 33-year-old Caucasian female with a left submandibular cystic mass measuring 4.7 cm x 2.9 cm, that was originally thought to be a plunging ranula and subsequently diagnosed as an epidermoid cyst. This report is meant to raise awareness of the possibility of a submandibular mass being an epidermoid cyst as well as appropriate workup, treatment, and prognosis of epidermoid cysts in the submandibular region. This report also describes a unique approach to a submandibular epidermoid cyst of which the submandibular gland is divided for access to the cyst for safe and effective excision. To the author's knowledge, this surgical approach has not been described in the literature for a submandibular epidermoid cyst.