Introduction

A mucous cyst (MC) is a benign, common, mucus-containing cystic lesion of the minor salivary glands in the oral cavity. Some authors (₁)prefer the term mucocele since most of these lesions are not true cysts in the absence of an epithelial lining. The lesions can be located directly under the mucosa (superficial mucocele), in the upper submucosa (classic mucocele), or in the lower corium (deep mucocele). Two types of MC occur based on the histologic features of the cyst wall: a mucous extravasation cyst formed by mucous pools surrounded by granulation tissue (92%) and a mucous retention cyst with an epithelial lining (8%)(₂,₃).

Mucoceles represented the 15th most common oral mucosal lesion, with a prevalence of 2.4 cases per 1000 people. Although the prevalence in children is not known, it is estimated to be higher than in adults. The studies show a high frequency in children and the association of this reactive lesion with head and neck trauma(₃). Mucoceles of the anterior lingual salivary glands (glands of Blandin and Nuhn) are relatively uncommon, with only isolated case reports and case series in the literature. This type of mucocele represents an estimated 2-8% of all mucoceles. Superficial mucoceles are typically located in the soft palate, the retromolar region, and the posterior buccal mucosa. They represent approximately 6% of all mucoceles. Multiple superficial mucoceles have been reported in a small number of patients(₄,₅) .

Salivary mucoceles (MC) are much more common in the lower lip, but they may also occur in other locations (the floor of the mouth, the cheek, the palate, the retromolar fossa, and the dorsal surface of the tongue; however, these lesions spare the upper lip)(₅). Clinically it appears as a discrete, more or less soft, fluctuant, painless, swelling of the mucosa. The size varies from a few millimetres to several centimetres in diameter, but 75% of the lesions are smaller than 1 cm in diameter. In most cases, diagnosis can be established from clinical details, although a histopathological study is necessary to confirm the diagnosis(₆,₇). The most effective treatment involves complete surgical extirpation.

The objective of the present study is to evaluate the clinicopathological characteristics of labial mucocele

Material And Methods

Eighteen cases of labial mucocele were studied at the School of Oral Medicine at the University of Murcia from 2000 to 2005, using a protocol in which clinical (age when first presented, colour, consistency, length of evolution and size) and histopathological variables were estimated. Helsinki rules were followed and the informed consent of each of the patients was obtained (Fig1,2).

Figure 1

Figure 1: Pink nontender nodule on the inner mucosa of the lower lip.

Figure 2

Figure 2: Measurement of the size oral mucocele

All cases involved surgical removal using the same technique. Local anaesthesia around the presumed mucocele was obtained with the application of topical 20% benzocaine on a 2 X 2-inch gauze followed within several minutes by the submucosal injection of 1% lidocaine with 1:100,000 epinephrine(Normon SL, Barcelona Spain). The extirpation was done including the immediate adjacent glandular tissue. ( Fig3) After the surgical intervention , 600mg ibuprofen was prescribed to the patients after every 8 h. The histopathological studies of the stages of extravasation were evaluated by means of Seifert's criteria (₅).( Fig4)

Figure 3

Figure 3: Macroscopic image of extirpation of oral mucocele

Figure 4

Figure 4: Histological image of lesion Hematoxylin Eosin x30

Results

The age range was 5 to 65 years, with an average age of 25 years. Of the 18 subjects, 11 were male (61.1%) and 7 women (38.9%). All were of Caucasian origin. Only one mucocele occurred in the upper lip, the rest being in the lower lip. One was bilateral. Most patients mentioned a gradual swelling of the lip (Table 1),of varying size. The interval from the time the patient first noticed the lesion to professional evaluation ranged from 3-24 weeks. The size varied from 2-15 mm diameter. All lesions presented as an exophytic mass, often with a polypoid appearance.

Figure 5

Table l: Labial Mucoceles . Patients clinical features

Of the mucoceles examined, 88% were of the extravasation type and 11% retention. Of the 16 classified as of the retention type, 12.5% were in the initial stage, 31.25% in the resorption stage and 56.25% in the final stage. All the mucoceles were extirpated surgically by the above described procedure and there were only two cases of recurrence in the one year follow-up period. No case of bleeding or secondary infection occurred and postoperative pain was minimal according to the patients' accounts.

Discussion

This study also confirmed that the mucocele frequently occurs on the lower lip; however, the actual formation mechanism is still unclear, although it is known to be favoured by a traumatic aetiology. The lesions can be located directly under the mucosa (superficial mucocele), in the upper sub mucosa (classic mucocele), or in the lower corium (deep mucocele). They usually occur singly and only very rarely bilaterally (only one case in our study). Mucoceles are painless asymptomatic swellings that have a relatively rapid onset and fluctuate in size. Clinical presentation depends on the depth of the lesion, while the colour depends on the size and its nearness to the surface. Superficial MC; the mucus accumulates immediately below the mucosa, resulting in small translucent vesicles (0.1-0.4 cm in diameter) in the soft palate, the retromolar region, and the buccal mucosa. In time, these blisters burst spontaneously or by trauma, leaving shallow ulcers or erosions. In the study we haven't found any cases of superficial mucocele.

The Classic MC .the size varies from a few millimeters to several centimeters in diameter, but 75% of the lesions are smaller than 1 cm in diameter. Eventually, the surface of the lesion turns irregular and whitish due to multiple cycles of rupture and healing caused by trauma or puncture. When the mucus accumulates in the deep soft tissues, the presentation is of an enlarging, painless mass assuming the pink coloration of the mucosa.

Diagnosis is made from the clinical characteristics and confirmed by biopsy (₁,₂,₃,₄). Patients with superficial MC require reassurance only(₈). Partial or total electrodessication and intralesional injections of triamcinolone acetonide have been reported as treatments of an MC; however, these are not routinely used. The most effective treatment is complete surgical extirpation of the lesion, including the immediately adjacent tissue. Aspiration of the mucocele contents often results in recurrence and is not appropriate therapy, except to exclude other entities prior to surgical excision(₁,₇) In the study we haven't found secondary complications (infection, bleeding, pain) we observed only two recurrence occurred during the follow-up year.

Laser ablation, cryosurgery, and electrocautery are approaches that have also been used for treatment of the conventional mucocele. The advantages of laser over cryosurgery consist of less discomfort in the postoperative period, less oedema and irritation, and a reduced healing time. (₉,₁₀,₁₁,₁₂,₁₃,₁₄,₁₅,₁₆) A disadvantage of this therapeutic alternative is the requirement of specialized

Surgical excision is the most commonly used method (₁, ₅, ₁₃) although if extirpation is not complete recurrence is frequent. Baurmash HD (₁) showed that there are 3 possible approaches to the management of mucoceles of the lower lip which also apply. The small lesion can be completely excised, making sure to include the associated salivary gland tissue as well as any marginal glands before primary closure. Large mucoceles are best treated with an unroofing procedure (marsupialization).The third procedure involves the dissection of the mucocele along with the servicing mucous glands. This technique is performed on moderate sized lesions. As in the excision technique, all marginal glands should be removed before primary closure.

Recently, the use of a micromarsupialization (₁₇) technique for mucoceles in pediatric patients has been reported. This technique involves the placement of a 4.0 silk suture through the widest diameter of the lesion (dome of the lesion) without engaging the underlying tissue. A surgical knot is made, and the suture is left in place for 7 days. Patients need to be educated about suture replacement; they must return to have the suture replaced if it should be lost during the 7-day period. The idea behind this alternative treatment for mucoceles of minor salivary glands is that re-epithelization of the severed duct occurs or a new epithelial-lined duct forms, allowing egress of saliva from the minor salivary gland. The recurrence rate after a short follow-up period has been 14% in pediatric patients.

Correspondence to

Dra. P. López Jornet Hospital Morales Meseguer 2planta Clínica Odontológica Universitaria Medicina Bucal, C/ Marques de los Velez s/n Murcia 30008, SPAIN Tel. 968/ 230061 Fax 968239565 e-mail: majornet@um.es