Internalize Info of the Week: A Frog in Your Throat, the Ranula (Mucous Cyst)

Ever had a frog in your throat? How about a frog under your tongue? This week I came across an interesting case of just that, called a ranula.

A ranula is a cyst that is located under the tongue. The name comes from the Latin word for “little frog,” Rana, which is also the scientific genus name. The cyst is named so because it looks like the neck of a frog when it croaks (see picture), because of its thin wall and transparent blue color.

The cyst is caused by an obstruction in a minor salivary gland duct or sublingual gland duct. They can be congenital, or acquired most likely from trauma. The cyst may be located near the submandibular gland duct (Wharton’s duct) and the lingual nerve which may affect talking and eating. However, they are usually painless.

 A specific type of ranula may plunge down through the mylohyoid muscle below, and is so termed a “plunging ranula.” This type of ranula is visible from outside the mouth because it causes a mass under the chin.

The incidence of ranulas are rare (my ENT preceptor sees about one per year), and plunging ranulas are even rarer. Treatment involves surgical excision, being careful to spare Wharton’s duct and the lingual nerve, with removal of the sublingual gland as well. The sublingual gland is removed with the cyst, because it significantly lowers the recurrence rate. If the cyst does come back it becomes much harder to remove again.

Sources:

Blair, Elizabeth A., and David E. Eibling. "Mucosal Lesions of the Oral Cavity, Tongue, and Oropharynx." Expert Guide to Otolaryngology. Ed. Karen H. Calhoun, Mark K. Wax, and David E. Eibling. Philadelphia, PA: American College of Physicians-American Society of Internal Medicine, 2001. 260. Print. ACP Expert Guide Series.

Eibling, David E. "Salivary Gland Disorders." Expert Guide to Otolaryngology. Ed. Karen H. Calhoun, Mark K. Wax, and David E. Eibling. Philadelphia, PA: American College of Physicians-American Society of Internal Medicine, 2001. 446-47. Print. ACP Expert Guide Series.

Van De Graaff, Ryan L. "Ranulas and Plunging Ranulas." Emedicine.medscape.com. Ed. Daniel J. Kelley, Francisco Talavera, Peter S. Roland, Christopher L. Slack, and Arlen D. Meyers. WebMD, 24 Feb. 2010. Web. 18 Nov. 2011. <http://emedicine.medscape.com/article/847589-overview#showall>.

Vorvick, Linda, and David Zieve. "Mucous Cyst." University of Maryland Medical Center Medical Encyclopedia. University of Maryland Medical System, 2 Aug. 2009. Web. 18 Nov. 2011. <http://www.umm.edu/ency/article/001639all.htm>.