Oral mucocele: Review of literature and a case report.

Mucocele is the most common lesion of the oral mucosa, which results from the accumulation of mucous secretion due to trauma and lip biting habits or alteration of minor salivary glands. Mostly they are two types based on histological features which as follows: Extravasation and retention. Mucoceles can appear at anywhere in the oral mucosa such as lip, cheeks and the floor of the mouth, but mainly appear in the lip. Diagnosis is mostly based on clinical findings. The most common location of the extravasation mucocele is the lower lip. Mucoceles most probably affect young patients but can affect all the age groups. They may have a soft consistency, bluish, and transparent cystic swelling, history of bursting and collapsing due to which resolves themselves then refilling which may be repeated. The treatment of choice is surgical removal of the mucocele.

Mucocele are defined as mucus-filled cavities, which can appear in the oral cavity, appendix, gallbladder, paranasal sinuses, and lacrimal sac.[12] The term mucocele is derived from a Latin word, mucus and cocele means cavity.[3] Mucocele is the 17th most common salivary gland lesions seen in the oral cavity.[4] This is the result of accumulation of liquid or mucoid material due to the alteration in the minor salivary gland which causes limited swelling,[5] which are characterized by a rounded, well-circumscribed, transparent, and bluish-colored lesion of variable size. Mostly they are soft in consistency and fluctuate while on palpation. Mucocele is painless and have a tendency to relapse.[67] They are mostly subdivided into two types: I. Mucus extravasation type, which is regarded as being a result of trauma, like lip biting. II. Mucus retention type, which results from the obstruction of the duct of a minor and/or accessory salivary gland.[189] Mucocele clinically appear as an asymptomatic vesicle or bulla with a pink or bluish-color, and their size may vary from 1 mm to several centimeters and affect both genders in all age groups,[10] with the peak age of incidence between 10 and 20 years.[1] The Lower labial mucosa is the most frequently affected site, but can also develop in the cheek, tongue, palate, and floor of the mouth, where it is called as ranula.[1] Mucocele can arise within a few days after minor trauma, but then plateau in size. They can persist unchanged for months unless treated. The diameter may range from a few millimeters to a few centimeters. If left without intervention, an episodic decrease and increase in size may be observed, based on rupture and subsequent mucin production.

Our case report aimed to explain the history, clinical features, and surgical removal of mucocele using a simple surgical technique, which helps to enhance the knowledge of the general dental practitioner.

Case Report

A 9-year-old male child came to the pediatric specialty dental clinic along with parents with the chief compliant of swelling in left lower lip region. The presenting illness showed that swelling present in the inner aspect of the lower lip in 73, 74 regions [Figure 1a and b] for past 3 months, which was initially small and progressed to the present stage. The child had also reported trauma on the lower lip 5 months back. Swelling was painless, and no past medical history like fever or malaise was present.

Figure 1

(a and b) Mucocele in lower lip, in relation to 73, 74 (c), 21 in cross bite relation

On examination of the lesion, it was soft, fluctuant and palpable with no increase in temperature, oval in shape. On intra-oral examination, erupting 11, 21 seen in which 21 was in cross bite relation [Figure 1c]. Generalized soft debris and calculus in the lower anterior region were present. Routine blood investigations were done, and the values were in the normal range.

Finally, the case was diagnosed as a mucocele on the basis of the history of trauma and clinical features. The treatment was planned and explained to the parents. Once obtained parent concern, treatment was performed. Scaling and restoration were done during their first clinical visit. Surgical removal of the lesion was planned and performed by placing an incision vertically; therefore splitting the overlying mucosa and then resecting the mucocele from the base was done [Figure 2a and b]. Hence, the chances of re-occurrence are less. The suture was placed [Figure 3a] and removed after 7 days. Acrylic inclined plane was given for correction of crossbite in relation to 21 and periodically monitored and removed once cross bite corrected. Parents were instructed to come for regular recall visit and patient regularly reviewed at 3 months interval for more than 30 months and no recurrence were noted [Figure 3b].

Figure 2

(a) Surgical removal of the lesion (b) Surgically removed mucocele

Figure 3

(a) Sutured area (b) Review after 7 days

Discussion

Mucocele is a common lesion of the oral mucosa, which can affect the general population. Mucocele can arise from an alteration of minor salivary glands due to a mucous accumulation.[5] Yamasoba et al. 1990 highlighted two etiological factors in mucocele: Traumatism and obstruction of salivary gland ducts.[11] Mucocele of the minor salivary gland are very rarely larger in diameter and moreover always superficial. Extravasation mucocele are caused by a leaking of fluid from ducts or acini to surrounding tissue. This type of mucocele is commonly found in the minor salivary glands. Physical trauma can cause a leakage of salivary secretion into surrounding submucosal tissue.

Diagnosis is mainly based on clinical findings; The appearance of mucoceles is pathognomonic[3] and location of the lesion, history of trauma, rapid appearance, variations in size, bluish-color, and the consistency are some of the important factors[12] to be considered before the final diagnosis are made.

Literatures showed oral habits such as lip biting/sucking is one of the etiologic factors for the oral lesions such as irritation fibroma and mucocele.[13] Radiographic evaluation is needed to rule out if sialoliths are considered a contributing factor in the formation of oral and cervical ranulas. The fine needle aspiration cytology demonstrates the mucus retention phenomenon. The chemical analysis could disclose protein content and high amylase. The localization and determination of the origin of the lesion can be done by computed tomography scanning and magnetic resonance imaging.[11] Palpation can be helpful for a correct differential diagnosis. Lipomas and tumors of minor salivary glands present no fluctuation while cysts, mucoceles, abscess, and hemangiomas show fluctuation.[14]

Conventional treatment is the surgical extirpation of the surrounding mucosa and glandular tissue below the muscle layer. With a simple incision of the mucocele, the content would drain out but the lesion would reappear as soon as the wound heals.[15] Surgical excision with removal of the involved accessory salivary gland has been suggested as the treatment. Marsupialization will only result in re-occurrence.[16]

The excised tissue must be submitted to the pathological investigations to confirm the diagnosis and rule out the salivary gland tumors. In our case, mucocele once removed and submitted to the pathological department to confirm the diagnosis. Laser ablation, cryosurgery, and electrocautery are approaches that have also been used for the treatment of the conventional mucocele with variable success.[11]

Conclusion

Mucocele are mostly benign and self-limiting nature, primarily diagnosed based on clinical findings followed by definitive diagnosis based on the histopathological investigation. Most of the reported literature showed lesion arose followed by trauma and habitual lip biting. Hence, a school based educational awareness program for both children and parent at a 6 months interval and interception of the oral habit among children is the key factor. Patient undergoing orthodontic therapy should be monitored periodically for areas of irritation in the oral mucosa. Complete excision has been the easiest way of treatment choice, and recurrence has been associated if the lesion removed incompletely. Our patient reviewed properly at 3 months interval for more than 30 months. During review, prognosis was excellent, and no recurrence was found.