Background. The plunging ranula is a relatively uncommon phenomenon which represents a mucus escape reaction occurring from disruption of the sublingual salivary gland. We present a series of 20 patients managed at Green Lane Hospital (Auckland, New Zealand) over a 9-year period.
Methods. A retrospective review of 13 patients with this condition was undertaken, and a prospective study was conducted on 7 patients. Information was collected on age, sex, ethnic origin, history of onset, predisposing factors, treatment, and outcome of treatment.
Results. The patients were all young adults with a median age of 31 years. The sex distribution was relatively equal, with 11 men and 9 women. All patients were Maori or Pacific Island Polynesians. Six patients gave a clear history of preceding trauma to the neck or oral cavity. Two recurrences were seen, both in patients who had had the sublingual gland excised via a cervical approach. Five patients sustained lingual nerve damage during surgery. Full function recovered in four patients, but the complication was still present in the fifth patient at 2 years, after which he was lost to follow-up.
Conclusions. Plunging ranulas appear to occur with greater incidence in the Maori and Pacific Island Polynesian populations. The precise etiology of their predisposition is unknown, although local trauma or inherent mylohyoid dehiscences may play important roles. Removal of the sublingual gland via either a cervical or intraoral approach is important in the management of this condition. Excision of the pseudocyst is probably unnecessary and places surrounding structures at risk of damage, but a biopsy of the pseudocyst wall is important to confirm the diagnosis.