by Nancy W. Burkhart, RDH, EdD
Your patient today is a 30-year-old male named James. He arrives at the practice for a six-month recall appointment with no unusual past history during his 11 years with your practice. He arrives early, and he tells you that he needs to see the dentist due to a swelling in the floor of his mouth (see Figure 1). He appears somewhat concerned and tells you that the swelling has been present for about four days. After an exam, he is referred to an oral surgeon with a probability of a ranula. After removal and tissue biopsy, the diagnosis by an oral pathologist was that of a ranula.
Etiology: The ranula results from an injury to the ducts in the floor of the mouth that involves the sublingual gland duct (Bartholin’s ducts), and occasionally the submandibular gland duct (Wharton’s duct). A ranula may also be classified as a “plunging ranula” when it extends into and past the mylohyoid muscle. At this point, the clinician will observe a definite swelling extraorally (see “Additional Common Terms”).
Method of transmission: The ranula is not caused by a fungal, viral, or bacterial agent and cannot be transmitted from one individual to another.
Pathogenesis: A ranula is a descriptive term for the mucocele occurring in the floor of the mouth, and the mucocele itself is another clinical term. The mucus extravasation phenomenon (not lined with epithelium) is often used interchangeably with the term mucocele. Other authors prefer the term “mucous escape reaction” when referring to the mucocele. Regardless of the choice of either term that is used, they are caused by trauma and rupture to the salivary duct.
A separate entity is the salivary duct cyst, and these are designated as cysts with epithelial linings. Salivary duct cysts involve some blockage of the duct that restricts the release of saliva. These are not classified as mucoceles.
Epidemiology: There is no sex predilection, and younger age groups are affected more often due to trauma.
Perioral and intraoral characteristics: The ranula often appears as a bluish swelling (hence, the Latin name rana for frog-appearing, as a frog’s underbelly). The swelling will often appear somewhat translucent with a smooth surface. Ranulas may appear balloon-like with changes in the appearance and size.
Distinguishing characteristics: The clouded blue hue is a clinically distinguishing characteristic of the ranula. The blue hue depends upon how close to the surface the mucin may pool. The ranula may also increase or decrease in size at any given time, as the pool of mucin or saliva increases or decreases. Patients report that the lesion appears larger when they eat and this is due to the increased production of saliva secretion during eating.
Ranulas occur lateral to the midline. Cysts such as the dermoid cyst usually occur in the midline.
Significant microscopic characteristics: The ranula specimen is walled off by granulation tissue enclosing the mucin pool. Ductal dilation is evident with an inflammatory response (see Figure 2).
Dental implications: Depending upon the size of the ranula, the patient may have trouble with speech, movement of the tongue, and a sense of irritation.
Differential diagnosis: Dermoid cysts, salivary duct cysts, and neoplasms are possible diagnoses. Determination or diagnosis cannot be made clinically since both the mucous extravasation phenomenon and a salivary duct cyst appear clinically similar and must be viewed microscopically. Techniques such as sialography or radiographs can detect the involvement of stones in the ducts which would denote salivary gland blockages due to sialoliths.
Treatment and prognosis: The preferred treatment of the ranula is controversial. The most debated element is whether the ranula itself should be removed. Some practitioners believe the ranula should be removed; some believe that the gland needs to be removed along with the ranula (although removal of the salivary glands may risk nerve damage). Others perform a less invasive technique called marsupialization, and some advocate sclerotherapy (injection of Streptococcus pyogenes incubated with benzylpenicillin OK-432). Aspiration is also a technique with marsupialization for recurrences.
Patel et al. (2009), in a retrospective review study, concludes that ranulas need only evacuation with removal of the sublingual gland. It is reported that removal of a ranula places the marginal mandibular and hypoglossal nerves at unnecessary risk. The study evaluated 864 cases from 1990 to 2007. Recurrence was reported by practitioners in 63% of cases, with nonrecurrent complications cited as tongue hypesthesia, bleeding/hematoma, and postoperative infection. The authors concluded that data indicated the fewest complications resulted from removal of the sublingual gland with ranula evacuation.
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Patel MR, Deal AM, Shockley WW. Oral and plunging ranulas: What is the most effective treatment? Laryngoscope June 5, 2009. In press.
About the Author
Nancy Burkhart, RDH, EdD, is an adjunct associate professor in the department of periodontics at Baylor College of Dentistry and Texas A&M Health Science Center in Dallas. Nancy is also a co-host of the International Oral Lichen Planus Support Group through Baylor (www.bcd.tamhsc.edu/lichen). She is the coauthor of General and Oral Pathology for the Dental Hygienist.
Additional Common Terms
Mucous extravasation phenomenon — Swelling is due to the rupture of the duct. These are never epithelial lined lesions. Granulation tissue forms around the pooled mucin, and an inflammatory process begins.
Mucous escape reaction — This term is interchanged with mucous estravasation phenomenon stated above. Swelling is due to the rupture of the duct. These are never epithelial lined.
Salivary duct cyst — Swellings are due to obstruction of the outflow of the duct because of a blockage such as mucin. As the name implies, the cyst has an epithelial lining.
Sialoliths — Calcified structures that develop within the ducts. Calcium salts, mucous, bacteria, epithelial cells, foreign bodies, or combinations comprise the stones.
Ranula — A descriptive clinical term that denotes a swelling in the floor of the mouth. When the term is used, it is essentially a large mucocele in the floor of the mouth.
Plunging ranula — The lesion extends into and past the mylohyoid muscle. Clinically, extraoral swelling of the tissue is evident.
Marsupialization — A surgical procedure that allows evacuation of the contents of the lesion, and removal of the roof of the lesion, thereby providing a drainage site for release of subsequently accumulating materials. The lesion is then allowed to heal by secondary intention. In the case of a cyst, the lesion would be completely removed with suturing of the edges of the remaining lesion area to the surrounding normal tissues. This allows the edges of the remaining lesion area to merge with the surrounding normal tissues and the surface epithelium.