Introduction

Oral ranulas are cystic lesions located on the floor of the mouth that arise from obstruction of the excretory duct of the sublingual gland. It is formed by rupture of excretory duct followed by extravasation of the mucus and accumulation of saliva into the surrounding tissue which forms a pseudo cyst that lacks the epithelial lining ^{(1). There are many methods in the literature for the treatment of ranulas including excision of the ranula only, excision of the ranula and the ipsilateral sublingual gland, marsupialisation and cryosurgery(2, 3), but the two widely practiced techniques are marsupialisation i.e unroofing of cyst (2) and sublingual gland excision. Recent studies have shown that surgical excision of the ranula along with the sublingual gland excision is a standard method of treatment. By doing these technique there is a risk of damaging the surrounding anatomical structures like lingual nerve and submandibular duct, which are close to the sublingual gland (4). Hence marsupialisation is still practiced to avoid injury to the surrounding anatomical structures, despite of reported recurrence rates of 61 to 89% (5) . Here with presenting a case report of oral ranula and its management in 11 year old male patient.}

Review of the literature

Ranula was reported by Hippocrates and Celsius (6). Ranula is derived from the Latin word ‘rana’ which means ‘‘frog’‘, because this lesions in the floor of the mouth resemble the bulging underbelly of a frog (7). Oral ranula is an infrequent pathology (8,9), usually occurring in children and adolescents. (9-13)

In the literature there are various studies on ranula, specific to children aged between 0-15 years (Table 1). Gul et al.(12) estimate the incidence of congenital ranula as 0.74%.Oral ranulas are most prevalent in females(8,19,21). According to the literature,(11,20,21) the most common site of oral ranula is on the left side of the floor of the mouth. Oral ranulas ranges from 0.5 to 3.3 cm. in diameter (4, 22). Ranulas are generally asymptomatic, although large ranula can cause aesthetic and functional problems (4, 22).

Figure 1

Table 1: Comparison of various studies on ranula in children

There are various methods of treating oral ranula. Garofalo S et.al (9) evaluated the effectiveness of orally administered Nickel Gluconate-Mercurius Heel-Potentised Swine Organ Preparations D10/D30/D200, a homo-toxicological agent and concluded that medication acts to stimulate pseudocyst re- absorption and glandular repair and also aids in improving the physiologic functioning of the gland.

Surgically ranula can be treated by excision of the cyst with or without excision of the ipsilateral sublingual gland, marsupialization, cryosurgery, CO2 laser excision and radiotherapy. Spontaneous resolution may be another option for paediatric population. If the lesion does not resolve after 6 months of observation then, surgical treatment is recommended (23).

Sublingual gland excision removes the source of the mucus and thus significantly decreases the risk of recurrence (23), but there are associated complication with surgical excision of ranula like injury to Wharton’s duct, obstruction of the sublingual gland, lingual nerve injury, sensory impairment of the tongue, recurrence and the development of a cervical ranula (Table 2)(4,18,22).

Figure 2

Table 2: Complication rates associated with procedures for treatment of ranula (8, 12)

Carbon dioxide laser is used in limited patients where there is good success to remove the cyst (24). Radiation therapy is done in patient who cannot tolerate surgery. Low doses, from 20-25 grays (Gy), are effective (25).

Marsupialisation is the oldest and most widely reported treatment for ranula. Though marsupialization is not in favour because of excessive failures, a high recurrence rate [anywhere from 61% to 89%, as reported in the literature] (5) and the high incidence of iatrogenically caused cervical ranula (26), ^{is still used to avoid potential surgical injury to adjacent structures when removing the sublingual gland.}

Marsupialisation involves 'unroofing' the cyst and tacking the edges of the cyst to adjacent tissue with the placement of a silk suture or seton into the dome of the cyst under local anaesthesia (2). ^{This is left in place while an epithelial tract forms, to allow for mucus drainage between the surface and the underlying salivary glandular tissue. Packing the cyst cavity with gauze for 7 - 10 days also improves the success rate. With the simple addition of packing the entire pseudocystic cavity with gauze after its unroofing, the rate of recurrence is minimized. Baurmash HD has recommended that oral ranula can be treated initially by marsupialization with packing and, if there is recurrence, then the offending sublingual gland should be excised(26). Alternatively sclerosing agents such as Bleomycin and OK-432 can be used to increase the success in treatment (15) Keqian Zhi et.al have reported two infant patients treated by marsupialization showed no recurrence of lesion with follow-up 24 months (27).}

Complete removal of a ranula is technically very difficult to achieve as it involves an extremely fine mucosa that will usually rupture on excision. Among the various surgical procedures, marsupilization has no complication associated except for higher recurrence rate. Here with presenting a case report of oral ranula in 11 year old boy who is treated with marsupilization considering it as the most ideal treatment for ranula (23).

Case report

An 11 year old boy reported to the Department of Pedodontics and Preventive Dentistry ITS-CDSR, Muradnagar, Ghaziabad with the chief complaint of a painless swelling below the tongue on the right side of the oral cavity for the past 4 months. The swelling started about 4 months back and increased gradually to attain its present size. There was no history of pain, but the patient had difficulty in speech, mastication and swallowing.

On examination, a 1.5 x 2cm dome-shaped, fluctuant swelling was seen in the floor of the mouth on the right side (Figure 1) swelling was seen attached to the right ventral surface of the tongue. The submucosal swelling was painless and fluctuant on palpation.

Figure 3

Figure: 1 Pre operative photograph

Aspiration biopsy yielded thick, viscous fluid and histopathological examination (HPE) revealed it to be mucous. Based on the aspiration & clinical findings the swelling was provisionally diagnosed as ranula. Other hematological and biochemical investigations including Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR) were all within normal limits. Chest x-ray was normal. After routine preoperative investigations, as the size of the cyst was small (< 2 cm) and it was superficial in nature, a conservative approach of marsupialization of ranula was planned. Local anaesthesia was given. The marking of the cystic swelling of the ranula was done by tacking the edges of the cyst to adjacent surrounding mucosa with resorbable suture, followed by de-roofing of the cystic lesion. The cavity which resulted from marsupialization was packed with betadine gauze (10% povidine –iodine topical antiseptic solution) and the pack size was gradually cut short as per the obliteration of the defect. The patient had an uneventful postoperative course and fully recovered. A tissue was sent to HPE for confirmation. HPE report confirmed the specimen to be ranula (Figure 2a, 2b,2c,2d). The case was followed up for 18 months at bimonthly interval. There is no reoccurrence of the lesion (Figure 3). Patient is still under follow up.

Figure 4

Figure 2a: Marking of cystic wall; Figure 2b: De-roofing; Figure 2c: Specimen; Figure 2d: Signs of healing after one week of marsupilization

Figure 5

Figure 3: Post operative follow up of 18 months

Discussion

Obstruction of excretory ducts or extravasations and subsequent accumulation of saliva from the sublingual gland in the tissue are responsible for the formation of ranulas (28-31).

Ranula is formed from one of the two processes:

Partial obstruction of a sublingual duct can lead to formation of an epithelial-lined retention cyst which is unusual, occurring in less than 10% of all ranula

Trauma can lead to formation of ranula. If a duct is obstructed, there is build up of secretory back-pressure leading to salivary duct rupture with mucus being forced into the surrounding tissues. Alternatively, trauma causes direct damage to the duct or acini, leading to mucus extravasation and forms a pseudocyst.

Based on the formation ranula can be classified into two groups, simple (intraoral)) and the plunging (cervical) type. Simple ranulas are more common than plunging type. A simple ranula are formed by localized collection of mucus within the floor of the mouth and may arise from the submandibular duct or from the body of the sublingual gland (32). In plunging ranula, ranulas will attain sufficient fluid pressure as to herniate through the mylohyoid muscle and produce swelling within the neck (33, 34,38).

Differential diagnosis of ranula should include dermoid cyst, teratid cyst, lymphangioma, mucocele of the minor salivary gland, lymphoma and HIV- related lymphadenopathy.CT and MRI imaging studies can be helpful in supporting a diagnosis of and in determining the origin of the lesion (34).

With this literature background marsupialization was opted as treatment choice in our case as this technique is simple, conservative and is not associated with damage to the important anatomic structures in this location (20). With the simple addition of packing the entire pseudocystic cavity with betadine soacked gauze after the deroofing of the cystic lesion, the rate of recurrence is minimized (26). Also, there is enough documentation to support this technique as treatment of choice (7). There is a need to do marsupialization for several times to resolve a large ranula. If ranula in oral cavity does not resolve after marsupialization, then surgical removal of the sublingual gland and pseudo cyst is recommended.

Conclusion

Though sublingual gland excision is considered as the most effective treatment for ranula, in children this procedure is very difficult as it involves an extremely fine mucosa that may rupture on excision also there is risk of injury to the lingual nerve and sublingual duct. Hence marsupilization is suitable and effective treatment for intraoral ranula (<2 cm) in children.