Giant sublingual epidermoid cyst resembling plunging ranula.

Epidermoid and dermoid cysts represent less than 0.01% of all oral cavity cysts. We describe a rare case of large epidermoid cyst in floor of mouth, with an oral as well as submental component resembling plunging ranula reported in the literature from India. We present a case of a 16-year-old girl with complaints of a mass in sublingual region, difficulty chewing, and dysphagia for about 5 months. Fine-needle aspiration cytology showed keratin flakes and proteinaceous material. Contrast-enhanced CT oral cavity was done and showed 7.0 × 5 × 4.5 cm well-circumscribed non-enhancing cystic mass extending into the floor of the mouth. On examination, a firm swelling was noticed in the submental area, extending down to the thyroid notch. The patient underwent surgical removal of the mass. On histopathology, acidophilic stratum corneum and basophilic dot like staining of stratum granulosum, which is the hallmark of an epidermoid cyst, were seen.