An oral mucocele is a common, harmless, fluid-filled cyst that appears on the inner surface of the mouth. Also known as a mucous cyst, it results from an accumulation of mucus. While often painless, it can be bothersome as a small bump in the mouth.
Common Causes
Oral mucoceles develop due to trauma or obstruction of the minor salivary glands or their ducts. When these glands are injured, saliva is disrupted, causing mucus to leak into the surrounding connective tissue and form a cyst. This leakage leads to inflammation and swelling, resulting in the characteristic fluid-filled sac.
Accidental lip biting or cheek chewing are frequent causes of this trauma. Habits such as lip sucking, chronic inflammation from tobacco use, or persistent contact with a sharp tooth can also damage salivary ducts. Oral piercings, previous oral surgery, or aggressive toothbrushing can lead to the formation of a mucocele. An obstruction of a salivary gland duct can prevent mucus from flowing out, leading to its accumulation and the development of a mucocele.
Appearance and Symptoms
An oral mucocele presents as a soft, dome-shaped lesion inside the mouth. These cysts usually range from a few millimeters up to 2 centimeters. Their color appears clear, bluish, or pinkish due to the contained mucus, and they have a smooth, round surface.
While they can occur anywhere in the mouth where minor salivary glands are present, the inner surface of the lower lip is the most common site. Other locations include the inside of the cheek, the tongue, or the floor of the mouth, where a mucocele is termed a ranula. Oral mucoceles are painless unless they are irritated or grow large enough to interfere with speaking, chewing, or swallowing. They may fluctuate in size, sometimes rupturing spontaneously and releasing a salty fluid, only to reform later.
When to See a Dentist
Many oral mucoceles resolve on their own, rupturing and healing within three to six weeks. However, if a mucocele persists for more than six weeks, increases in size, causes discomfort, interferes with speech or eating, or begins to bleed, seek dental evaluation. A dentist can diagnose the lesion, ruling out other oral conditions that may present similarly.
Attempting to drain or rupture a mucocele at home is not recommended due to the risk of infection and tissue damage. If treatment is necessary, a dental professional may suggest options cryotherapy, laser treatment, or surgical excision of the cyst. The affected salivary gland may also be removed to prevent recurrence.