ORIGINAL RESEARCH–GENERAL OTOLARYNGOLOGY Plunging ranula: Congenital or acquired? Randall P. Morton, MSc, FRACS, Zahoor Ahmad, MD, FRACS, and Prabha Jain, FRACR, Manukau City, New Zealand No sponsorships or competing interests have been disclosed for this article. ABSTRACT OBJECTIVE: To review our clinical experience with plunging ranula and examine the evidence in support of our impression that plunging ranula has a genetic basis. STUDY DESIGN: Case series with chart review. SETTING: Secondary otolaryngology service. SUBJECTS AND METHODS: Review of the medical records of a clinical series of 80 consecutive plunging ranulas in 77 patients was conducted, with recording of clinical and radiological findings, surgical treatment, and outcome. A literature review using MEDLINE and OLD MEDLINE was performed. RESULTS: The majority of plunging ranulas had no intraoral component on clinical examination, although evidence of mucus extravasation from the sublingual gland could be found both ra- diologically and histologically in all cases. There were four pa- tients with bilateral plunging ranula and one instance of siblings with unilateral plunging ranula. Maoris and Polynesians comprised more than 82 percent of our cases; this was a significant overrep- resentation of these ethnic groups (P  0.0001). A very strong predominance of cases of Chinese origin was also evident in the literature. CONCLUSION: The clinical findings and the supporting data from the literature, when viewed in light of information relating to the known anatomical anomaly of a dehiscence in the my- lohyoid muscle and ectopic sublingual gland lying below the plane of the mylohyoid, appear to support the case for a genetic basis for this unusual clinical entity. © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. A plunging, or cervical, ranula is a pseudocyst in the neck formed by mucus extravasation from the sublingual gland (SLG). 1-3 It has been described as a rare condition 2,4 and may be categorized as those with and those without an oral component. 5 The cervical-only clinical picture was thought to be very rare; up to 1991 only four such cases had been reported. 4 Later reports, however, imply that the cervical-only type of plunging ranula is actually not so rare; a recent series of pediatric plunging ranulas reported only seven of 21 pa- tients with an intraoral component, 2 and Zhao et al’s 6 large series of 186 plunging ranulas had combined oral-cervical presentation in only 66 (35%) cases. A plunging ranula generally presents in the second or third decade of life, 6,7 although several papers have de- scribed ranulas in children under 10 years of age, 1,2,6,8 even in a one-year-old. 9 The latter case led the authors to suggest that a plunging ranula could be a congenital condition. 9 The possibility of a congenital predisposition to the de- velopment of plunging ranula has been suggested by others on the basis of the observation that there are anomalies in the mylohyoid muscle 10 with dehiscence in the muscle that allows possible herniation of part of the SGL. Such herni- ation or subluxation has been defined in anatomical dissec- tions 11,12 and in radiological assessments 13 as well as in various surgical reports of plunging ranula. 4,8 Although the presence of such mylohyoid dehiscence and SLG herniation may predispose to development of plunging ranula, 14 at least occasionally the extravasation of mucus passes poste- riorly and enters the neck at the posterior border of the mylohoid, 15 presumably because there is no dehiscence or SLG herniation in those cases. From our experience with plunging ranula, we think that the suggestion of a genetic basis for its formation has merit. This paper summarizes features from our own clinical series that has led us to this view and also reviews the relevant literature from this perspective. Methods All patients seen in the Department of Otolaryngology– Head and Neck Surgery from January 2001 to December 2008 with a diagnosis of plunging ranula were entered on a register and followed prospectively. This study was con- ducted in accordance with the Auckland Regional Ethics Committee requirements for clinical audit and approved by the Counties-Manukau Clinical Board. Clinical, laboratory, and radiological features were recorded, as well as patient demographics, surgical findings, and clinical outcome. The diagnosis was made from a combination of clinical signs, the presence of mucoid fluid on aspiration, the findings of amylase in the aspirate, and radiology (ultrasound, CT, or MRI) that showed a communication with the sublingual space or a herniated SLG. Received March 22, 2009; revised September 3, 2009; accepted October 14, 2009. Otolaryngology–Head and Neck Surgery (2010) 142, 104-107 0194-5998/$36.00 © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2009.10.014