An oral mucocele is a common, benign, fluid-filled swelling that develops in the soft tissues of the mouth. This lesion appears as a translucent, dome-shaped lump, often exhibiting a bluish tint due to the pooled fluid lying just beneath the surface of the mucosa. The most frequent location for a mucocele is the inner surface of the lower lip, although it can occur anywhere minor salivary glands are present. These lesions are generally painless, though they can cause discomfort and concern due to their sudden appearance and fluctuating size.
What Oral Mucoceles Are
A mucocele is classified as a pseudo-cyst because, unlike a true cyst, the fluid-filled sac lacks an epithelial lining. This swelling originates from the minor salivary glands, which are tiny glands scattered throughout the oral lining responsible for producing saliva. The core issue involves the disruption of the normal flow of mucus from these glands into the mouth. Mucoceles are typically small, with about 75% measuring less than one centimeter in diameter.
There are two primary classifications: the mucous extravasation phenomenon and the mucous retention cyst. The extravasation phenomenon is the more common type, resulting from the rupture of a salivary gland duct. This rupture causes mucus to spill into the surrounding connective tissue, forming a pool of fluid.
The retention cyst occurs when a salivary gland duct is blocked rather than ruptured. This obstruction leads to the build-up of mucus within the duct and the gland itself, causing the duct to expand. The retention cyst is more likely to be found in older adults, whereas the extravasation type is common in children and young adults.
Causes and Formation Mechanism
The development of an oral mucocele is usually traced back to localized physical trauma or injury to the minor salivary gland ducts. The most frequent triggers are habits like lip biting, cheek chewing, or accidental injuries sustained during eating or dental procedures. This mechanical impact can sever the excretory duct.
When the duct is severed or lacerated, the mucin—the main component of saliva—is no longer channeled properly into the mouth. Instead, the mucus leaks out and pools in the submucosal tissue adjacent to the gland. This spilled mucus triggers a localized inflammatory response, which results in the formation of a granulation tissue wall around the fluid pocket, giving the lesion its characteristic dome shape.
Management and Treatment Options
Treatment for an oral mucocele often begins with a period of watchful waiting, as many small, superficial lesions resolve on their own. The thin roof of the mucocele may rupture spontaneously, allowing the fluid to drain and the lesion to flatten out. This self-healing process can take anywhere from a few weeks to several months.
For larger, persistent, or frequently recurring mucoceles, surgical intervention by a dentist or oral surgeon is recommended. The standard procedure involves complete surgical excision of the mucocele along with the minor salivary gland feeding it. Removing the associated gland is necessary to prevent recurrence, which is the primary risk after treatment.
Minimally invasive options are also available, including marsupialization, where the lesion is opened and the edges are sutured to the adjacent mucosa to create a new, open duct. Other techniques include cryotherapy, which uses freezing to destroy the lesion, and laser ablation. Studies suggest there is no significant difference in the recurrence rate among conventional surgical excision, laser ablation, and marsupialization techniques.