What is a ranula?

A ranula is a fluid collection, or cyst, that forms in the mouth under the tongue. It is filled with saliva (spit) that has leaked out of a damaged salivary gland. Instead of the saliva draining from the glands directly into the mouth, one of these glands is damaged, so the saliva leaks into the tissues next to the gland and forms a bubble.

Sometimes a ranula forms without a known cause. Other times, trauma to the mouth, from oral surgery, getting hit in the face or biting the lower lip, can start one.

There are two types of ranulas. A simple (or oral) ranula is when the cyst stays in the floor of the mouth, underneath the tongue. A plunging (or diving) ranula is when the cyst grows down under the mouth and into the neck. It is rarer than a simple ranula and may occur along with a simple ranula.

Ranulas are one of the most common salivary gland disorders. Ranulas most often occur in the sublingual glands beneath the tongue, which empty onto the floor of the mouth.

Other common salivary gland disorders are salivary duct stones and salivary gland tumors.

Symptoms of a ranula

A clear or bluish bubble-like growth on the floor of the mouth is the main symptom of a ranula. Since they don’t typically cause pain, they may go unnoticed until the cyst grows in size. Then it may cause problems with speech, swallowing and, occasionally, breathing if it grows large enough to press on the trachea (windpipe). A plunging ranula may present as a neck mass with or without the bubble in the floor of mouth. 

Diagnosis of a ranula

A pediatric otolaryngologist, a physician who specializes in the ears, nose and throat (ENT), will examine the child. Depending on the location and type of problem, the doctor may press on (palpitate) the child’s neck or look inside their mouth, pushing on the floor of the oral cavity.

Some doctors can make a diagnosis based on the appearance and location of the cyst. Your doctor may order image tests to define the extent of the swelling or to confirm that your symptoms are caused by a ranula and not something else, such as an abscess, a dermoid cyst or a branchial cleft cyst.

The doctor might order imaging studies. These can include:

  • a CT scan, which uses a combination of X-rays to take detailed pictures of the inside of the body
  • an MRI, which uses strong magnets and radio frequency waves to produce images of the body
  • an ultrasound of the neck, which uses sound waves to create images inside of the body

Treatment of a ranula

Small, simple ranulas that don’t cause problems may not require treatment. Some cysts may disappear on their own. Treatment is necessary, however, for enlarged simple ranulas, especially when swelling interferes with swallowing or speaking, and for most plunging ranulas.

Children who require treatment for a ranula will see a pediatric otolaryngologist (ENT). At Children’s Hospital of Philadelphia, pediatric ENT surgeons on our Head and Neck Disorders team will care for children with ranulas.

There are a few ways the ranula can be treated:

  • Incision or needle aspiration: Depending on its size, your doctor can make an incision and drain the cyst to decrease swelling or use a needle to withdraw the fluid. These treatments are often temporary and the cyst reappears in about two-thirds of the time because the underlying damage still exists.
  • Marsupialization: The surgeon makes a slit in the cyst and sutures the edges to maintain an opening. This procedure allows the cyst to drain freely.
  • Surgery: This involves removal of the cyst and the damaged sublingual gland. Removing the cyst alone may not resolve the issue since the problem originates in the gland. If your doctor removed just the cyst and preserves the gland, a new cyst may develop.

Outlook for children with ranulas

After surgery, the ranula should not return. The rest of the child’s salivary glands will make enough saliva that eating will not be a problem.

Reviewed by Conor M. Devine, MD