Mouth Cyst or Mucous Cyst – Types, Causes, Prevention & Treatment

A mouth cyst may irritate you quite often because you feel a bump inside the mouth. It often presents as a thin fluid-filled sac on the inside of your mouth. It is also known as a mucous cyst or mucocele, and it is harmless and painless in most cases. Usually, mouth cysts heal on their own, but sometime they might need intervention by a dentist.

Furthermore, we see, the difference between a mucous cyst and a ranula, which are the most common mouth cysts. We will also find out about their signs and symptoms, causes, prevention, and treatment.


What is a mouth cyst?

Usually, a mouth cyst occurs on the inner side of the lips. But it can also form on the tongue, palate or roof of the mouth, cheeks, floor of the mouth or around intraoral piercings.

A mouth cyst is a clear fluid filled bump in the oral cavity which may or may not be painful. A cyst on the floor of our mouth is called a ranula or frog-like, and a cyst on the gum is known as an epulis.

The mucous cyst, on the other hand, is bluish and clear and contains clear fluid. Your dentist can usually diagnose a mucous cyst just by looking at it. (1)

Types of mouth cysts

Mouth cysts are mainly of two types as True cysts and Pseudo (false) cysts. True cysts are of dental and bony origin and can be classified in the following types –

  • Dentigerous Cyst
  • Kerato Ossifying cyst or tumor
  • Calcifying cyst
  • Globulo Maxillary cyst, etc

Pseudocysts are soft tissue related cysts which we commonly see in our mouth; they are Mucocele and Ranula. Ranula can be further classified into cervical ranula or plunging ranula (in the neck region) and oral ranula.

Difference between a mucous cyst and ranula

Based on origin

  • Mucoceles, are of minor salivary gland origin. Also referred to as mucous retention cysts. The superficial mucous cyst, a common variant, has features that resemble a mucocutaneous (on the skin) disease.
  • Ranulas are merely mucoceles that occur in the floor of the mouth and usually involve the major salivary glands.
  • Specifically, the ranula originates in the sublingual gland (below the tongue), and, sometimes from the minor salivary glands at this location.

Based on Causation

  • Oral ranulas are caused by mucus extravasation from minor salivary glands, whereas cervical ranulas are mucus extravasation along the planes of the neck.
  • The mucous cyst, on the other hand, arises within the submandibular (below the lower jaw) gland and is a mucus retention cyst. (2)

Signs and symptoms of mucous cyst

Mucoceles often end up on the inside of your lower lips, your gums or the roof of your mouth. Mucoceles may have these characteristics:

  • Moveable and painless
  • Soft, round, dome-shaped
  • Pearly or semi-clear surface or bluish
  • 2 to 10 millimeters in diameter

Signs and symptoms of Ranula

Ranula appears as a clear sometimes bluish translucent growth on the floor of the mouth is the primary symptom of a ranula. They don’t cause pain, so you may not notice it unless the cyst enhances in size.

  • If you have a simple ranula, then the swelling is confined to the sublingual gland (below the tongue).
  • This is the smallest of these three paired salivary glands around the throat and mouth.
  • Another type of ranula is plunging ranula, which occurs when a simple ranula ruptures. This causes a mass in the submandibular space (the facial space of the head and neck).
  • A plunging ranula can produce additional symptoms, such as difficulty in swallowing, difficulty in speaking, and tracheal compression. (3)

Causes of mouth cysts – Mucocele

Lip biting or sucking lips

Your saliva flows from a salivary gland through thin tubes (ducts) into your mouth. When one of these ducts become damaged or blocked, a mouth cyst forms. This often happens if you repeatedly bite or suck on your lower lip or cheek.


Getting hit in the face head-on could also disrupt the duct. This causes seepage of saliva and leads to the mucous cyst.

Mucus extravasation & duct blockade

Mucus seeps out, pools, becomes walled off and causes a cyst-like swelling. A similar buildup happens when the duct has become blocked.

Causes of mouth cysts – Ranula

The cause of a ranula is unknown, and the swelling occurs spontaneously. But some leading causes are:


Ranula occurs after injury to the floor of the mouth (like an oral surgery). An injury can damage the ducts that move saliva from the salivary gland into the mouth, causing a blockage.

Improper drainage of saliva

When saliva can’t properly drain, it accumulates in the gland and forms a dome-shaped cyst. Trauma can include biting the lower lip or cheek or getting hit in the face.

Plunging or diving ranulas are caused by a rapidly growing simple ranula that ruptures.

Diagnosis of mouth cysts

Some mouth cysts that have no symptoms do not require a visit to your dentist. But see a dentist if the cyst enlarges and runs a risk of the lesion rupturing.

Your dentist may order imaging tests to examine the extent of the swelling or to confirm that a cyst causes your symptoms.

Imaging tests to diagnose them include –

  • CT scan, which uses a combination of radiations to take detailed pictures of the inside of the body
  • Magnetic Resonance Imaging uses amplified magnetic fields to produce images of the body
  • Ultrasound of your neck, which uses sound waves to create images inside of the body

These tests can also distinguish a ranula and mucous cyst from conditions with similar symptoms and features, such as an abscess, a dermoid cyst, or a branchial cleft cyst. (4)

Mucous cyst treatment

Mucoceles often disappear without treatment. But sometimes they enlarge so don’t try to open them or treat them by yourself. See a dentist for expert advice.

These are majorly the two types of treatment a dentist most commonly uses –

Removing the gland

The dentist or doctor may use a scalpel or laser to remove the salivary gland. Local anesthesia numbs the pain.

Helping a new duct to form, called marsupialization, this technique helps a new duct form and helps saliva leave the salivary gland.

The dentist or doctor –

  • Disinfects the area
  • Puts a stitch through the mucous cyst and ties a knot
  • Gently presses out saliva
  • Removes the stitch after about a week

Other types of treatment

That may bring down swelling or prevent the need for surgery include steroid injections and medications applied to the surface of the mucous cyst.

Ranula treatment

The treatment options are the same as that of mucous cyst except small ranulas may not require surgery since they are small and less problematic. Some cysts disappear without treatment.

Treatment is necessary for enlarged ranulas when swelling interferes with swallowing or speaking.

  • Depending on its size, your dentist can cut and drain the cyst to decrease swelling. Even if this treatment is effective, fluid may re-accumulate.
  • Surgery is used only for larger ranulas. This calls for a removal of the cyst and the parent sublingual gland entirely. Removing the cyst and not the gland may not resolve the issue since the problem originates in the gland. If your dentist preserves the gland, a new cyst develops.
  • An alternative treatment option for a ranula is marsupialization same as a mucous cyst.

Home treatment for mouth cyst

Gamma-linolenic acid (oil of primrose) is useful. Talk to your dentist before using oil of primrose about its effectiveness in detail.

Can a ranula cause complications?

Complications may present with some enlarged ranula which includes rupture as well as difficulty swallowing and speaking. Relapse is a possibility after draining that cyst.

There may also complications associated with surgery. Which include temporary tongue numbness, post-surgery hematoma, and infection. Signs of infection are fever, chills, and pain. See a dentist if you have signs of infection.



There is barely anyway in which you can prevent the occurrence of these mouth cysts except refraining yourself from trauma and lip biting.

Over to you on the mucous cyst

Mouth cyst or mucous cyst is potentially harmless until they open. However, a mouth cyst may or may not open on its own. If the cyst is left untreated, then a permanent bump may form.

Mouth cysts are harmless but see your dentist if something new forms in your mouth as it may be something more dangerous too. It is mandatory to make sure that your dentist evaluates this area by examination.


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