Treatment of Labial Mucocele by Intralesional Injection of Dexamethasone: Case Series

Introduction

Salivary mucocele is a common lesion of the minor salivary glands, frequently appears as a single bluish or translucent swelling on the lower lip. Blunt trauma such as lip biting or trauma from adjacent teeth to minor salivary glands may lead to rupture and/or occlusion of the excretory ducts, and terminate to extravasation and accumulation of salivary mucus inside the connective tissue. Two types of mucoceles are known: extravasation type which is mostly seen on the lower lip in the majority of cases; and retention type usually located in the cheek or palate of older patients, completely lined by ductal epithelium and occurs less frequently (1,2).

The diameter of mucoceles ranges from a few millimeters to centimeters. Many patients report periodic discharge of viscous fluid from the lesion. The lower lip is the region mostly affected by mucoceles(1,2).

The differential diagnosis of mucocele includes fibroma, lipoma, hemamgioma, traumatic neuroma, schwanomma and salivary gland tumors. Fibroma, lipoma, traumatic neuroma, and schwanomma do not show episodic fluctuations in size over time. Meanwhile, they are different from mucocele in terms of their frequent location, and associated symptoms for example schwanomma is more frequent in the tongue, and traumatic neuroma is accompanied with pain. Hemangioma feels fewer firms to palpation, whereas mucoceles are elastic and fluctuant masses unless they are draining or become chronic with a surrounding fibrous tissue. When located superficially, hemangioma produces a deep blue (if cavernous in origin) to a purple coloration (when originates from capillaries) coloration, while a superficial mucocele appears with a blue hue. Cavernous hemangiomas blanch under pressure due to their emptiability nature (positive diascopy test), but this is not the case for mucocele. Minor salivary gland tumors are most commonly found in the palate and because of their neoplastic nature and progressive growth they do not have a history of episodic fluctuations in size (3-7).

The overall prognosis is good and various treatments have been proposed such as surgical excision of the lesion with or without removal of the associated gland(1, 2). Because of several unpleasant complications after surgery like lip disfigurement, and damage to adjacent ducts with further development of satellite lesions, many noninvasive methods have been introduced to treat mucocele including cryosurgery, laser micro marsupialization, Gluconate-Merucurius Heel-Potentised Swine Organ Preparations, CO₂ laser ablation, topical and intralesional injection of corticosteroids, and OK- 432(8-12). Intralesional injections of corticosteroids have been used to treat salivary mucocele with different rates of success (11). Therefore, we decided to evaluate the effect of a highly potent corticosteroid (dexamethasone) on the management of salivary mucocele when injected intralesionally.

Case Report

Nine patients diagnosed clinically by two oral medicine specialists as having salivary mucocele on their lower lips at the Department of Oral Medicine at Shahid Beheshti University of Medical Sciences Dental School from Oct 2010 to Oct 2012 were entered the study; two of them had recurrent mucoceles. Diagnosis of mucocele was mainly based on its clinical appearance characteristics such as exophytic dome-shaped lesion with smooth surface, bluish color, soft to firm consistency, history of trauma and fluctuation in size (6,13).

Patients with mucoceles on oral rather than labial mucosa, or those not willing to receive injections, or having contraindications for systemic corticosteroids (such as history of tuberculosis, hyperglycemia, hypertension, and osteoporosis) were excluded from the study.

We injected 1ml of 8mg/ml dexamethasone by insulin needles into the base of lesions to prevent any leakage and less discomfort and pain. No local anesthesia was required. Each patient received three consecutive shots with one-week intervals. We examined all patients on days 7, 14, and 21 to evaluate their response and gave them the 2^nd and 3^rd injections. The size of lesions was measured by means of a dental caliper (Huaxian Gaoping Yuanda Diamond Products Factory, Henan, China) in mm.

All patients were followed later in a mean of 12.5 months (range 6–20 months) after their last injection. Demographic data of patients as well as clinical characteristics of their lesions were summarized in Table 1.

Table 1. Characteristics of mucocele patients underwent intra lesional dexamethasone therapy

^*M: Male, ^†F: Female, ^¶TT: Teeth Trauma, ^**TLB: Trauma due to Lip Biting, ^***R: Reduction in size.

Our patients aged from 17 to 35 years with the mean of 26.6. There were four men and five women. Duration of lesions varied from 10 days to one year. ^. In the present study, normal mucosal appearance was seen in five cases whereas four patients had lesions in bluish color. In eight cases out of nine, there was a history of chronic trauma from lip biting or adjacent teeth. The maximum size of all lesions was 1.5 cm. Seven lesions resolved completely following injection (Fig. 1a, b); and two cases showed reduction in size. An excisional biopsy was taken only from Patient 7 whose lesion was reduced in size after three consecutive injections, but still had interference to eating. Histopathologic study showed normal labial mucosa with no signs of retention phenomena (Fig. 2a, b).

Medical Ethics Committee of Shahid Beheshti University of Medical Sciences approved the study ethically in accordance with Helsinki Declaration. An informed written consent was obtained from all patients before injection.

Figure 1. The full size mucocele before (a) and after (b) treatment with intralesional dexamethasone

Figure 2a, b. Photomicrographs (H & E staining at *10 and *40 magnifications respectively) of mucocele remnants after intralesional dexamethasone injection showing normal mucosal architecture without any retention phenomena (Courtesy to Dr. F. Mashadi-Abbas)