Ranula
A fluid-filled cyst on the floor of the mouth
Quick Facts
- Type: Salivary gland cyst
- Location: Floor of the mouth, under the tongue
- Cause: Blocked or injured sublingual gland
- Treatment: Often surgical removal
Overview
A ranula is a fluid-filled swelling, or cyst, that forms on the floor of the mouth beneath the tongue. It develops from the sublingual salivary gland when the gland is injured or its duct is blocked, causing saliva to leak out and collect in the surrounding tissue. The name comes from the Latin word for frog, because the swelling can resemble a frog's translucent throat.
Most ranulas appear as a soft, dome-shaped, sometimes bluish swelling under the tongue. A less common type, called a plunging ranula, extends down into the neck and causes a swelling there. Ranulas are not cancerous, but they can grow large enough to interfere with speaking, eating, or swallowing and often need treatment to remove the affected gland.
Symptoms
Symptoms depend on the size and type of the ranula and may include:
- A soft, painless swelling on the floor of the mouth, often on one side
- A bluish or translucent appearance to the swelling
- A lump in the neck if it is a plunging ranula
- Discomfort or difficulty with speaking, eating, or swallowing if the swelling is large
- A swelling that may change in size over time
Ranulas are usually painless unless they become infected, in which case they can become red, tender, and warm. Rapidly enlarging swelling or any difficulty breathing or swallowing requires prompt medical attention.
Causes
A ranula forms when saliva escapes from the sublingual gland and pools in the tissue, usually because of:
- Blocked duct: A blockage causes saliva to back up and form a cyst.
- Injury to the gland: Trauma to the floor of the mouth, including from dental procedures or accidental injury, can damage the gland or duct.
- Spontaneous leakage: Sometimes saliva leaks without an obvious cause, forming a collection in the surrounding tissue.
When the leaked saliva tracks downward through the muscles into the neck, it forms a plunging ranula.
Risk Factors
- Injury or trauma to the floor of the mouth
- Recent dental or oral surgical procedures
- Younger age, as ranulas are common in children and young adults
- Anatomical variations of the sublingual gland
Diagnosis
Diagnosis is usually made by examining the characteristic swelling, with imaging used in some cases:
- Physical examination: A soft, often bluish swelling under the tongue is usually recognizable on inspection.
- Ultrasound: Can confirm a fluid-filled cyst.
- MRI or CT: Helpful for a plunging ranula to map how far it extends into the neck.
Imaging also helps distinguish a ranula from other cysts or masses when the diagnosis is unclear.
Treatment
Treatment depends on the size, type, and whether the ranula keeps coming back.
- Observation: Very small ranulas may occasionally be watched, as some resolve on their own.
- Surgical removal of the sublingual gland: Removing the affected gland is the most reliable treatment and has the lowest chance of recurrence.
- Marsupialization: A procedure that opens the cyst and stitches its edges to allow drainage, though it has a higher chance of recurrence.
- Draining alone: Simply draining a ranula often leads to it returning, so it is generally not a long-term solution.
For a plunging ranula, removing the sublingual gland usually resolves the neck swelling as well.
Prevention
- Ranulas cannot always be prevented, but reducing injury to the floor of the mouth may help
- Use mouthguards during contact sports
- Have oral and dental procedures done carefully by qualified providers
- Seek evaluation early for a new swelling under the tongue
When to See a Doctor
See a doctor or dentist if you notice a soft swelling under the tongue or a lump in the neck that does not go away. Seek prompt care if the swelling becomes red, tender, and warm, suggesting infection, or grows quickly. Seek emergency care if a large swelling causes difficulty breathing or swallowing.
Frequently Asked Questions
What is a ranula?
A ranula is a fluid-filled cyst on the floor of the mouth that forms when saliva leaks from the sublingual gland and collects in the tissue. It often appears as a soft, bluish swelling under the tongue.
Is a ranula dangerous or cancerous?
Ranulas are not cancerous. They are usually harmless but can grow large enough to interfere with speaking, eating, or swallowing, and a plunging type can cause neck swelling, so they often need treatment.
What is a plunging ranula?
A plunging ranula is a type that tracks downward through the muscles into the neck, causing a neck swelling in addition to, or instead of, a swelling under the tongue. Imaging helps map how far it extends.
How is a ranula treated?
The most reliable treatment is surgical removal of the affected sublingual gland, which has the lowest chance of recurrence. Simply draining the cyst usually leads to it returning.
Will a ranula go away on its own?
Some very small ranulas resolve without treatment, but most persist or recur and need a procedure. See a doctor or dentist for any swelling under the tongue that does not go away.
References
- MedlinePlus, U.S. National Library of Medicine. Salivary gland disorders.
- American Academy of Otolaryngology-Head and Neck Surgery. Salivary gland disorders.
- National Institute of Dental and Craniofacial Research (NIDCR). Salivary gland conditions.
- Mayo Clinic. Salivary gland disorders.