Plunging ranula: CT diagnosis.

A plunging ranula is a cystic mass in the submandibular area arising from an occluded sublingual gland. Fluid from the obstructed gland dissects between the fascial planes and muscle of the base of the tongue to the submandibular triangle. A plunging ranula can be readily identified preoperatively with computed tomography as a cystic mass in the suprahyoid anterior neck. Three case reports are presented.