Bilateral Plunging Ranulas in South Auckland: Evidence for a Genetic Basis

OBJECTIVES: We present a series of bilateral plunging ranula patients to examine the etiology, diagnosis, treatment, and prognosis of this condition. METHODS: A retrospective chart review was performed on all cases of plunging ranula treated at the Department of Otolaryngology-Head and Neck Surgery, Counties Manukau District Health Board, New Zealand, between 2001 and 2019. RESULTS: There were 17 patients with bilateral plunging ranulas from a total of 187 plunging ranula patients. Eight patients were of Pacific Island descent; six were Maori; and three were Asian. There were no European patients with bilateral plunging ranulas. There were three types of bilateral plunging ranula patients: 1) Metachronous plunging ranulas-Five patients presented with a unilateral plunging ranula with no evidence of a contralateral plunging ranula on initial imaging. Despite negative contralateral imaging findings, these patients developed a clinically evident contralateral plunging ranula 21 to 61 months later. 2) Synchronous plunging ranulas detected on imaging-Eight patients presented with a clinically evident unilateral plunging ranula but also had a contralateral plunging ranula detected on imaging. 3) Clinically evident synchronous plunging ranulas-Four patients presented with bilateral clinically evident plunging ranulas, which were also evident on imaging. Twelve patients underwent bilateral transoral sublingual gland excision and plunging ranula evacuation. CONCLUSION: All patients with a unilateral plunging ranula should be advised of the potential for developing contralateral disease, and this should be emphasized in patients of Pacific Island, Maori, and Asian descent. LEVEL OF EVIDENCE: 4 Laryngoscope, 2020.