| Ranula | |
|---|---|
 | |
| Specialty | Oral and maxillofacial surgery |
Aranula is a mucus extravasation cyst involving a sublingual gland and is a type ofmucocele found on the floor of the mouth. Ranulae present as aswelling ofconnective tissue consisting of collectedmucin from a rupturedsalivary gland caused by local trauma. If small and asymptomatic further treatment may not be needed, otherwise minororal surgery may be indicated.
A ranula usually presents as a translucent, blue, dome-shaped,fluctuant swelling in the tissues of the floor of the mouth. If the lesion is deeper, then there is a greater thickness of tissue separating from the oral cavity and the blue translucent appearance may not be a feature. A ranula can develop into a large lesion many centimeters in diameter, with resultant elevation of the tongue and possibly interfering with swallowing (dysphagia). The swelling is not fixed, may not show blanching, and is non-painful unless it becomes secondarily infected. The usual location is lateral to the midline, which may be used to help distinguish it from a midlinedermoid cyst.[1] Acervical ranula presents as a swelling in the neck, with or without a swelling in the mouth. In common with other mucoceles, ranulae may rupture and then cause recurrent swelling. Ranulae may be asymptomatic, although they can fluctuate rapidly in size, shrinking and swelling, making them difficult to detect.
Minor trauma to the floor of the mouth is thought to damage the delicate ducts that drain saliva from the sublingual gland into the oral cavity.[2] The lesion is amucous extravasation cyst (mucocele) of the floor of mouth, although a ranula is often larger than other mucoceles (mainly because the overlying mucosa is thicker).[3] They can grow so large that they fill the mouth. The most usual source of themucin spillage is the sublingual salivary gland, but ranulae may also arise from thesubmandibular duct or theminor salivary glands in the floor of the mouth. A cervical ranula occurs when the spilled mucin dissects its way through themylohyoid muscle,[1] which separates thesublingual space from thesubmandibular space, and creates a swelling in the neck. It may occur following rupture of a simple ranula.[4] Rarely, ranulae may extend backwards into theparapharyngeal space.[4]
The fluid within a ranula has the viscous, jellylike consistency ofegg white.
Thehistologic appearance is similar tomucoceles from other locations. The spilled mucin causes a granulation tissue to form, which usually contains foamyhistiocytes.[1]Ultrasound andmagnetic resonance imaging may be useful to image the lesion.[4] A small squamous cell carcinoma obstructing theWharton duct may require clinical examination to be distinguished from a ranula.[5]
A ranula is a type of mucocele, and therefore could be classified as adisorder of the salivary glands. Usually a ranula is confined to thefloor of the mouth (termed a "simple ranula").[6] An unusual variant is the cervical ranula (also called a plunging or diving ranula), where the swelling is in the neck rather than the floor of the mouth.[1] The term ranula is also sometimes used to refer to other similar swellings of the floor of mouth such as true salivary duct cysts,dermoid cysts andcystic hygromas.[1] The Latin wordrana means "frog" (ranula = "little frog").
Treatment of ranulae usually involves removal of the sublingual gland. Surgery may not be required if the ranula is small and asymptomatic.[2]Marsupialization may sometimes be used, where the intra-oral lesion is opened to the oral cavity with the aim of allowing the sublingual gland to re-establish connection with the oral cavity.
The lesion is usually present in children.[2] Ranulae are the most common pathologic lesion associated with the sublingual glands.[3]
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