# Ranula and Mucocele Management

## Introduction

Mucoceles and ranulas are common cystic lesions of the salivary glands frequently encountered by the OMFS surgeon. Mucoceles are the most common benign lesion of the minor salivary glands, while ranulas arise specifically from the sublingual gland in the floor of mouth. Proper classification, understanding of pathogenesis, and selection of appropriate surgical technique are essential to minimize recurrence.

## Pathogenesis

### Mucous Extravasation Cyst (Mucocele)

The mucous extravasation cyst results from traumatic disruption of a minor salivary gland duct. Mucin extravasates into the surrounding connective tissue, and the body walls off the mucin pool with a granulation tissue pseudocapsule, meaning there is no epithelial lining (not a true cyst). The most common causes are lip biting, trauma, and habitual cheek chewing. This type represents 90% of mucoceles.

### Mucous Retention Cyst

The mucous retention cyst is a true cyst with an epithelial lining (ductal epithelium) resulting from ductal obstruction without rupture (sialolith, scar, or tumor). It represents approximately 10% of mucoceles and is more common in older adults, occurring in major or minor glands.

## Mucocele

### Clinical Features

The lower lip is the most common site (60-70%), followed by the buccal mucosa, floor of mouth, and ventral tongue. The appearance is a dome-shaped, fluctuant, bluish-translucent swelling that is painless. Size is typically 1 to 2 cm and may fluctuate (rupture and refill cycle). It is most common in children and young adults with peak incidence at 10 to 20 years. Upper lip mucoceles are rare, and a swelling on the upper lip is more likely a salivary gland neoplasm and should be biopsied.

### Differential Diagnosis

The differential includes fibroma, hemangioma, lymphangioma, minor salivary gland tumor, and lipoma. Blanching with pressure (hemangioma) helps differentiate vascular lesions. Non-resolving or firm upper lip lesions require biopsy to rule out malignancy.

### Treatment

#### Excision

Complete excision of the mucocele with the associated minor salivary gland(s) is the gold standard. Under local anesthesia, an elliptical or circumferential incision is made, and the lesion is removed intact if possible with the underlying salivary gland tissue. The specimen is submitted for histopathologic examination, and the wound is closed primarily with absorbable sutures. The recurrence rate is 5 to 10% with complete excision including glands.

#### Marsupialization

Marsupialization involves creating a wide opening to decompress the cyst and allow re-epithelialization. The recurrence rate (15-30%) is higher than excision. It is useful in pediatric patients where cooperation for excision is limited and is often combined with packing or suturing the cyst wall to the surface epithelium.

#### Other Modalities

Cryotherapy with liquid nitrogen is useful for small superficial lesions. Laser ablation with CO2 or diode laser provides minimal bleeding and is good for recurrent lesions. Micro-marsupialization involves passing a silk suture through the lesion and tying it to promote fibrosis and collapse, making it a practical technique for pediatric patients. Intralesional corticosteroid injection has limited evidence and may reduce size temporarily.

![Clinical photographs showing the typical appearance and excision of a lower lip mucocele](images/mucocele-excision.jpg)

## Ranula

### Classification

#### Simple (Oral) Ranula

The simple ranula is a mucous extravasation cyst confined to the floor of mouth above the mylohyoid. It presents as a unilateral, bluish, fluctuant swelling in the sublingual space and is named for its resemblance to a frog's belly (rana = frog). It arises from the sublingual gland (most common) or rarely from Wharton's duct.

#### Plunging (Cervical) Ranula

In a plunging ranula, mucin extravasates through or around the mylohyoid muscle into the submandibular or submental space. It presents as a cervical swelling that may or may not have an intraoral component and can extend to the parapharyngeal space in extreme cases. It must be differentiated from dermoid cyst, thyroglossal duct cyst, branchial cleft cyst, lymphatic malformation, and submandibular gland tumor.

### Diagnosis

Clinical examination reveals a fluctuant, compressible floor of mouth mass (simple ranula) or a cervical mass with or without a floor of mouth component (plunging ranula). Aspiration yields viscous, straw-colored fluid with high amylase and protein content and low cell count. Ultrasound is the first-line imaging and shows a well-circumscribed anechoic lesion. CT or MRI is required for plunging ranula to delineate extent, with MRI being superior for soft tissue characterization. On MRI, the ranula shows low T1 signal, high T2 signal, and no enhancement, distinguishing it from solid neoplasm.

![MRI images showing a plunging ranula extending from the sublingual space through the mylohyoid into the submandibular space](images/plunging-ranula-mri.jpg)

### Treatment of Simple Ranula

#### Marsupialization

Marsupialization involves excision of the roof of the ranula (de-roofing) and suturing the cyst wall to the floor of mouth mucosa. It is a simple procedure with low morbidity but has a significant recurrence rate of 25 to 70%. It is acceptable as initial treatment, especially in children.

#### Sublingual Gland Excision (Sublingual Glandectomy)

Sublingual gland excision is the gold standard for simple ranula because it removes the source of the lesion. A transoral approach uses an incision in the floor of mouth mucosa. Wharton's duct and the lingual nerve are identified and preserved. The recurrence rate is dramatically lower at 0 to 4% compared to marsupialization alone. Morbidity is higher, with risk of lingual nerve injury (2-5%), Wharton's duct injury, and floor of mouth swelling.

#### Marsupialization with Sublingual Gland Excision

Many surgeons favor simultaneous excision at the time of marsupialization, as this combined approach achieves the lowest recurrence with acceptable morbidity.

### Comparison of Ranula Treatment Options

| Treatment | Technique | Recurrence Rate | Morbidity | Best Indication |
|-----------|-----------|----------------|-----------|-----------------|
| Marsupialization alone | De-roofing and suturing cyst wall to mucosa | 25-70% | Low | Initial treatment in children |
| Sublingual gland excision | Transoral removal of source gland | 0-4% | Moderate (lingual nerve risk 2-5%) | Gold standard for simple ranula |
| Marsupialization + sublingual gland excision | Combined approach | 0-4% | Moderate | Lowest recurrence with acceptable morbidity |
| Sclerotherapy (OK-432) | Intralesional injection | Variable | Low | Select plunging ranulas; alternative to surgery |
| Cervical drainage alone | External drainage without gland excision | 50-100% | Low | Insufficient as standalone treatment |

### Treatment of Plunging Ranula

Sublingual gland excision via a transoral approach is the treatment of choice. Removing the source (sublingual gland) causes the cervical component to resolve spontaneously. Cervical drainage alone without sublingual gland excision has a very high recurrence rate of 50 to 100%. A combined cervical and transoral approach may be necessary for large plunging ranulas that require cervical drainage in addition to sublingual gland removal. Sclerotherapy (OK-432) has been reported as an alternative in select cases.

## Superficial Mucocele

The superficial mucocele is a distinct clinical entity presenting as multiple small (1-3 mm) vesicles on the soft palate, retromolar pad, or buccal mucosa. They may rupture spontaneously, causing a burning or raw sensation. They are often misdiagnosed as vesiculobullous disease (pemphigoid, pemphigus). Many cases are self-limiting, with excision or laser ablation reserved for persistent lesions.

## Special Considerations

### Pediatric Patients

Mucoceles and ranulas are common in children. Congenital ranulas can present at birth or in the neonatal period. Micro-marsupialization with a silk suture is a well-tolerated office-based technique for children. Surgical excision under general anesthesia is performed if the lesion is recurrent or large.

### Recurrent Lesions

Recurrence after marsupialization alone is the most common management challenge. Definitive treatment requires excision of the source gland. For recurrent mucoceles, the mucocele is excised with all associated minor salivary glands in the area. For recurrent ranulas, sublingual gland excision is mandatory.

![Intraoral photograph showing a simple ranula in the floor of mouth and the transoral sublingual gland excision approach](images/ranula-sublingual-excision.jpg)

## Clinical Pearls

Upper lip salivary gland swellings are not mucoceles until proven otherwise, and biopsy should always be performed to exclude neoplasm. Sublingual gland excision is the definitive treatment for ranulas with recurrence rates of 0 to 4% compared to 25 to 70% for marsupialization alone. For plunging ranulas, transoral sublingual gland excision resolves the cervical component, and cervical drainage alone is insufficient. All excised specimens should be submitted for histopathologic examination to confirm the diagnosis. Micro-marsupialization is a practical, minimally invasive option for mucoceles in young children.

## References

1. Zhao YF, et al. "Clinical Review of 580 Ranulas." *Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology*. 2004;98(3):281-287.
2. Lai JB, Poon CY. "Treatment of Ranula Using Carbon Dioxide Laser -- Case Series Report." *International Journal of Oral and Maxillofacial Surgery*. 2009;38(10):1107-1110.
3. Patel MR, Deal AM, Shockley WW. "Oral and Plunging Ranulas: What Is the Most Effective Treatment?" *Laryngoscope*. 2009;119(8):1501-1509.
4. Re Cecconi D, et al. "Mucoceles of the Oral Cavity: A Large Case Series." *Journal of Oral and Maxillofacial Surgery*. 2010;68(12):3013-3017.