Mucocele is the most common lesion of the salivary glands. Mucoceles are the result of trauma. It results from either blockage or rupture of a salivary gland duct, with consequent leakage of saliva into the surrounding connective tissue stroma. Clinically, they present as a fluctuant swelling of the lower lip. It may change in the size during meals. Treatment is complete excision of the cyst.

The term ranula is reserved for mucoceles that arise when the duct of the sublingual gland has been damaged. The sublingual gland secretes continuously in the interdigestive period, whereas the other two major salivary glands only secrete in response to stimuli, such as eating.

A ranula is a type of mucocele

Mucocele

A "mucous cyst of the oral mucosa" is a clinical term that refers to two related phenomena: mucus extravasation phenomenon, and mucus retention cyst...

 found on the floor of the mouth

Mouth

The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

. Ranulas present as a swelling

Swelling (medical)

In medical parlance, swelling is the transient enlargement or protuberance in the body and may include tumors. According to cause, it may be congenital, traumatic, inflammatory, neoplastic or miscellaneous....

 of connective tissue

Connective tissue

"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...

 consisting of collected mucin

Mucin

Mucins are a family of high molecular weight, heavily glycosylated proteins produced by epithelial tissues in most metazoans. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most gel-like secretions, serving functions from lubrication to cell...

 from a ruptured salivary gland

Salivary gland

The salivary glands in mammals are exocrine glands, glands with ducts, that produce saliva. They also secrete amylase, an enzyme that breaks down starch into maltose...

 duct

Duct (anatomy)

In anatomy and physiology, a duct is a circumscribed channel leading from an exocrine gland or organ.-Types of ducts:Examples include:-Duct system:...

, which is usually caused by local trauma.

The Latin rana means frog

Frog

Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

, and a ranula is so named because its appearance is sometimes compared to a frog's underbelly.

Appearance

An oral ranula is a fluctuant swelling with a bluish translucent color that somewhat resembles the underbelly of a frog Rana

Rana (genus)

Rana is a genus of frogs. Species include such archetypal pond frogs as the common frog of Europe, brown frogs, and the New and Old World true frogs, including the various species of leopard frogs and the American bullfrog. Members of this genus are found through much of Eurasia, North America,...

. If it is deeper it does not have this bluish appearance. If it is large ( 2 or more cm.), it may hide the salivary gland and affect the location of the tongue. Most frequently it stems from the sublingual salivary gland, but also from the submandibular gland.

Though normally above the mylohyoid muscle

Mylohyoid muscle

The mylohyoid muscle is a muscle running from the mandible to the hyoid bone, forming the floor of the oral cavity. It is named for its two attachments, with the prefix "mylo" coming from the Greek word for "molar". These muscles are mesodermal in origin...

, if a ranula is found deeper in the floor of the mouth, it can appear to have a normal color. A ranula below the mylohyoid muscle is referred to as a "plunging or cervical ranula", and produces swelling of the neck with or without swelling in the floor of the mouth.

Ranulas measure several centimeters in diameter and are usually larger than mucocele

Mucocele

A "mucous cyst of the oral mucosa" is a clinical term that refers to two related phenomena: mucus extravasation phenomenon, and mucus retention cyst...

s. As a result, when ranulas are present the tongue may be elevated. As with mucoceles, ranulas may be subject to recurrent swelling with occasional rupturing of its contents. When pressed, they may not blanch.

Symptoms

Ranulas may be asymptomatic, although they can fluctuate rapidly in size, shrinking and swelling, making most ranulas hard to detect. However, if it gets large enough it may interfere with swallowing. The overlying mucosa is usually intact. The swelling is not fixed and is non-painful unless it becomes secondarily infected.

Histology

Microscopically, ranulas are cystic saliva filled distensions of salivary gland ducts on the floor of the mouth alongside the tongue, and lack a true epithelium.

Treatment

Treatment of ranulas could involve either marsupialization

Marsupialization

Marsupialization is the surgical technique of cutting a slit into a cyst and suturing the edges of the slit to form a continuous surface from the exterior to the interior of the cyst. Sutured in this fashion, the cyst remains open and can drain freely...

 or more often excision

Excision

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of both the gland and lesion. Ranulas are likely to recur if the sublingual gland or other gland causing them is not also removed with the lesion. There is little morbidity or mortality connected with treatment.

External links

• CT Scans