Overview

An oral mucocele is a painless and typically benign (non-cancerous) oral cavity lesion. The term “mucocele” originates from “mucus” and “cocele” which means cavity. Oral mucoceles form due to a breach of a salivary gland and/or its ducts, causing mucin (a constituent of saliva) to accumulate in the enclosing soft tissues. This may happen due to local trauma, lip-biting habits, pinching of the lips, and ductal obstruction. It presents itself as a transparent pink or bluish-coloured round lesion with clearly defined margins that can vary in size. An oral mucocele appears as a pouch-like mucus-overfilled swelling arising anywhere in the oral mucosa (inside lining of the mouth), for instance, on the lower lips, the floor of the mouth, the cheeks, the tongue underside, the palate, the upper lips, and the retromolar pad. These may be soft in consistency and fluctuate on palpation (feeling with your fingers).¹

Oral mucoceles are divided into two types based on histological features - mucus extravasation cysts and mucus retention cysts.  The lip is the most common site for mucus extravasation cysts. All age groups are affected, but it's more prevalent in young people of both sexes.

Causes of oral mucocele

Oral mucocele forms due to changes in the minor salivary glands and some accessory glands. The two most crucial factors contributing to the formation of these cysts are:

1. Local trauma - Physical injury or damage resulting in leakage of salivary secretions into the surrounding mucosal tissues. As a reaction to the leakage, inflammatory responses aggregate at the site of mucus accumulation, forming a cyst. This is called the mucus extravasation phenomenon, mucus extravasation cyst, or escape reaction. 

Blockage in the salivary gland ducts -  Retention mucoceles are formed after an expansion of the salivary gland duct due to its blockage either by sialolith (salivary stone) or dense mucus. The majority of retention cysts develop in the major salivary gland ducts. This is known as the mucus retention cyst.²  

Other causes may include:

• friction with the opposing tooth into the buccal mucosa (inner lining of your cheek);
• the habit of lip biting, lip chewing, lip sucking, and tongue thrusting;
• long-term usage of tobacco or smoking.³

Signs and symptoms of oral mucocele

Although oral mucoceles are harmless and painless, discomfort and problems in daily activities like difficulty in chewing, swallowing, and speaking are common in patients with large lesions. An oral mucocele, or mucous cyst, is a non-cancerous fluid-filled sac that commonly develops in the oral cavity. It typically forms due to an obstruction or rupture of a salivary gland duct, leading to an accumulation of mucin (a component of mucus) within the surrounding tissues. Oral mucoceles present the following clinical features:

• Colour - bluish or pinkish translucent vesicle or bulla (blister) due to fluid gathering in the cyst; the accumulated mucin below the mucous membrane shows a bluish tinge. However, in a deeper mucocele, normal colouration is seen.
• Swelling - small, painless and dome-shaped, ranging from a few millimetres to a centimetre or larger, located on the inner side of the oral cavity.
• Fluctuant or palpable - mucoceles are mostly fluctuating or squeezable in between fingers, and no pain is observed while palpating; a little discomfort might be experienced.
• Texture - soft and smooth consistency, filled with mucin.
• Site - on the lower lips, cheeks, mouth floor, tongue underside, palate, upper lips, and retromolar pad area. The most common site is the lower lips. When it is present on the floor of the mouth, it is known as a ranula. The term ‘ranula’ comes from the Latin word rana, which means ‘a frog’ due to the resemblance of the swelling to the translucent underbelly of the frog.
• Duration & recurrence - Patients usually report the lesion to last a few days to several years. Some cases show recurrent swellings that may burst and discharge the fluid contents sporadically, typically painless, but a bit of discomfort might be present. These lesions might reoccur after being removed or bursting and again be refilled themselves. 
• Pain - usually painless but there might be an irritation if accidentally bitten or if they interfere with normal day-to-day oral functions like speech or chewing.
• Self-recovery - in some cases, no treatment is required, and the mucoceles may recover independently after releasing the cyst fluid and the swelling might disappear naturally.
• Age groups - all age groups can suffer of this lesion, with no sex predilection, meaning both sexes  are equally affected.^{1, 2}

Mucus extravasation mucoceles are common in children and young adults whereas mucus retention cysts are predominant in adults. Mucus extravasation is not a true cyst because it lacks epithelial lining while mucus retention is a true developmental cyst lined by the epithelial lining.² When mucus extravasation mucocele develops from the sublingual gland (salivary gland located below the jaw) and its subsequent herniation (protrustion) via the mylohyoid muscle into submandibular space and beyond, the process is known as a plunging ranula.⁴

Management and treatment for oral mucocele

Some of the mucoceles are short-lived and they might subside on their own by bursting and further self-recovery. However, many lesions are chronic and depending on the patient’s age, impact on daily life, the severity of the pathology, and the nature of the lesion, in might require management by a healthcare professional. In both types - mucus extravasation and mucus retention, the treatment approach and management are dictated by the location, span, and dimension of the mucocele. These management procedures may include:

• Surgical incision - the most common method of treatment for this lesion is surgical removal of the surrounding mucous membrane and the glandular tissue up to the muscle layer. However, the lesion may reoccur after the healing process is completed. In the case of superficial mucocele, no treatment is required due to its self-resolving nature.
• Marsupialisation - small-sized mucoceles are surgically excised with the marginal glandular tissue but in larger mucoceles, to protect the vital parts, marsupialisation is preferred. There is not much difference in the treatment of extravasation and retention cysts as they both appear the same clinically. 
• Micromarsupilisation - involves relatively less pain and minimal trauma in pediatric patients. First, the size of the lesion is reduced by passing silk thread via the swelling at the largest point of the lesion and draining the fluid, followed by creating a surgical knot. After 7 to 8 days the suture is removed, giving time for mucocele to subside on its own. 
• Cryosurgery - cryosurgery is also giving promising results in many cases.
• Intralesional steroid injections - are used in some cases.
• CO₂ laser ablation - was proven to be beneficial as no acute inflammatory reaction and minimal blood loss occurs, and the treatment period is on the shorter side.
• Electrocautery -  used in some cases. ^{2, 4, 5}

In case of reoccurrences in severe patients, the entire accessory gland is removed surrounding the mucosa or the lesion that is feeding on the gland.

Diagnosis

The diagnosis of an oral mucocele can be completed by  following these points:

• Clinical diagnosis is a major factor. Collecting a patient’s medical history is a major and initial step in the diagnosis. The history is considered very seriously, for recollection of previous oral trauma instances. A mucocele’s appearance or presentation is its characteristic feature, and based on the past trauma record, site of lesion, rapid emergence, and differences in dimensions, consistency, and bluish colouration, the diagnosis is made. 
• Palpation is a reliable method of rejecting a differential diagnosis. Mucocele, abscess, and hemangiomas are fluctuant while lipomas and minor salivary gland tumours are non-fluctuant. An already burst/drained mucocele would be non-fluctuant and a long-standing mucocele with the infestation of fibrosis would be less fluctuant.^{1, 2}
• For the detection of a ranula, radiographs (x-rays) prove to be beneficial.
• Computed tomography and Magnetic resonance imaging (CT and MRI) give a clear picture of the localisation of these lesions. Chemical analysis can disclose high amylase and protein content.³
• The histopathologic study is essential as it depicts the entire granulation tissue. 
• is removed. Mucus extravasation and mucus retention mucoceles are also differentiated during a  histopathological examination.²
• Fine needle aspiration biopsy (FNAB)  can be used for differential diagnosis of angiomatous lesions.³

FAQs

How can I prevent an oral mucocele?

We all have episodes of eating without much care at times, either when we are in a hurry or for any other reason. While doing this, we might accidentally  hurt ourselves by biting our lips, mucosa, or cheeks. We can avoid oral mucoceles by carefully eating our food and avoiding trauma to our oral mucosa as much as possible. We should get rid of multitasking while eating and focus on our food which can prevent any accidental biting injuries. Lip-chewing and lip-sucking habits should also be given up. The use of tobacco or harmful chemicals should be avoided in order to maintain good oral hygiene. Good oral hygiene should also be practised in the form of teeth brushing and flossing.

How common is an oral mucocele?

In a general population, 2.4 out of 1000 people are affected by oral mucoceles.

Who is at risk of an oral mucocele?

People of all ages suffer from oral mucoceles but it's more prevalent in young people who more often have such habits or engage in activities that cause trauma to the oral cavity. Both sexes are equally affected. 

When should I see a doctor?

In most cases, mucoceles are self-resolving but you should consult a healthcare professional in case of difficulty with speaking, eating, chewing, or swallowing due to a large swelling.

Summary

Mucoceles are benign and self-resolving painless lesions. They might cause difficulty in day-to-day oral functions but in most cases they are harmless. They can be diagnosed initially with the help of patient’s medical history and further confirmed by histopathological studies. Trauma and lip-biting habits are the basic causative factors for mucocele formation. Careful eating should be considered to avoid any chance of accidental trauma to the oral cavity. Although most mucoceles are self-healing, in severe cases, complete surgical excision is the most effective treatment option. Recurrences are common in case of incomplete removal of the lesion. 

References

1. Nallasivam KU, Sudha BR. Oral mucocele: Review of literature and a case report. J Pharm Bioallied Sci [internet]. 2015 Aug [cited 2023 Jul 4];7(Suppl 2):S731-3. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4606697/
2. Ata-Ali J, Carrillo C , Bonet C , Balaguer J, Peñarrocha M , Peñarrocha M. Oral mucocele: review of the literature. J Clin Exp Dent [internet]. 2010 [cited 2023 Jul 4];2(1):e18-21. Available from: http://www.medicinaoral.com/odo/volumenes/v2i1/jcedv2i1p18.pdf
3. Bhargava N, Agarwal P, Sharma N, Agrawal M, Sidiq M, Narain P. An unusual presentation of oral mucocele in infant and its review. Case Rep Dent [internet]. 2014 Aug [cited 2023 Jul 4]; 2014:723130. Available from: https://doi.org/10.1155/2014/723130
4. Olojede ACO, Ogundana OM, Emeka CI, Adewole RA, Emmanuel MM, Gbotolorun OM, Ayodele AO, Oluseye SB. Plunging ranula: Surgical management of case series and the literature review. Clin Case Rep [internet]. 2017 Nov 29 [cited 2023 Jul 4];6(1):109-114. Avaialble from: ncbi.nlm.nih.gov/pmc/articles/PMC5771944/
5. Rao P, Hegde D, Shetty S, Chatra L, Shenai P. Oral Mucocele - Diagnosis and management. J Dent Med Med Sci [internet]. 2012 [cited 2023 Jul 4];2(2):26–30. Available from: https://www.interesjournals.org/articles/oral-mucocele--diagnosis-and-management.pdf

This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Dr Prerna Yadav

Bachelor of Dental Surgery- BDS, Kothiwal Dental College & Research Centre Moradabad, India

Dr. Prerna Yadav is an accomplished Dental Surgeon with 8 years of clinical expertise. With a passion for knowledge and research, she pursued an Advanced PG Diploma in Pharmacovigilance & Clinical Research. A Certified Medical Writer as well, Prerna possesses a unique blend of dental proficiency and medical communication finesse. Her journey is a testament to dedication and an unwavering commitment to both patient care and advancing medical knowledge.

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