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, 131:73-77, 2021.

The epidemiology of plunging ranula in South Auckland.

OBJECTIVES/HYPOTHESIS: Estimate the incidence rate and provide basic descriptive epidemiologic characteristics of plunging ranulas in a multi-ethnic population. STUDY DESIGN: Case series with chart review. METHODS: The study group comprised all Counties Manukau Health (CMH, Manukau City, Auckland, New Zealand) patients presenting to the CMH Department of Otolaryngology with a diagnosis of plunging ranula from January 2001 to December 2013, as recorded in the departmental case register. Non-CMH domicile patients were excluded. South Auckland comprised the base population, as serviced by CMH. The 2006 New Zealand census data was used for population demographics. RESULTS: A total of 134 cases of plunging ranula were identified. The overall annual crude incidence rate was 2.4 per 100,000 person-years. The gender specific incidence rate for males was 3.2 per 100,000 (95% confidence interval [CI]: 2.5. 3.9) and for females was 2.0 per 100,000 (95% CI: 1.5, 2.6). The overall age-adjusted annual incidence rate was 2.6 per 100,000 (95% CI: 2.1, 3.0). The age-adjusted incidence was highest among Maori (6.7 per 100,000, 95% CI 4.9, 8.4), followed by Pacific Island (4.4 per 100,000, 95% CI 3.2, 5.6), Asian (0.7 per 100,000, 95% CI 0.2, 1.2), and European population (0.6 per 100,000, 95% CI 0.3, 0.8). CONCLUSION: We have quantified for the first time the age-specific and age-adjusted incidence rates for plunging ranula by gender and ethnicity. The results show a likely underlying genetic predisposition for this condition, possibly with a superimposed environmental acquired factor relating to external, minor blunt trauma to the neck. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:2739-2743, 2016.