Oral mucocele in infant with an unusual presentation

Background

Oral mucocele represents a common lesion of the oral mucosa that results from a traumatisation of minor salivary glands resulting in mucous accumulation. It is a benign lesion that involves mucin aggregation causing limited swelling.1 Mucoceles of the oral cavity are classified as extravasation and retention types. The retention mucocele results from mucus retained in an epithelial-lined cavity usually a dilated duct of minor salivary glands.2 3 Extravasation mucocele is a pseudocyst without any epithelial covering, surrounded by a layer of inflammatory cells and then by a reactive granulation tissue made up of fibroblasts caused by an immune reaction.2–4 They are characterised by the accumulation of mucoid material, giving rise to a rounded, well-circumscribed transparent and bluish-coloured lesion of variable size. The consistency is typically soft and fluctuant in response to palpation. Mucocele is usually painless and may often tend to relapse.4

The incidence is high, in the order of 2.5 lesions per 1000 individuals. Indeed, mucocele is the most common minor salivary gland disorder and represents as the second most frequent benign soft tissue tumours of the oral cavity, following traumatic fibromas.3 4 The most common site of occurrence of mucocele is the lower lip, having no sex predilection and all age groups are susceptible, with the peak frequency reported in the second to third decades. They are rarely observed in infants; making the diagnosis and management of mucocele challenging.4 5

Histopathological analysis usually reveals the presence of granulation tissue, which may contain leukocytes, lymphocytes, plasma cells and foamy histiocytes. The lumen of the cavity is filled with an eosinophilic material containing a varied number of inflammatory cells. The treatment of choice for mucocele is surgical excision. Removal of the associated salivary glands is essential to prevent recurrence. Aspiration of the fluid does not yield long-term benefit. Management of mucocele at times could be difficult because surgical removal itself may cause trauma to the adjacent minor salivary glands, which might lead to the development of new mucocele.5 6

The present case report describes the rare occurrence of mucocele in a 5-month-old infant and emphasised on its management aspect.

Case presentation

A 5-month-old infant was brought to the outpatient department by his grandmother with the chief problem of swelling on the ventrolateral surface of tongue since birth. The history of present illness revealed that the swelling gradually increased in size since past 5 months. The child was in good general health and no other associated symptoms were reported. Patient’s grandmother did not give any history of trauma and considering the fact that none of the deciduous teeth were erupted; chances of trauma due to tooth were also over-ruled.

Intraoral examination revealed an elevated, fluid-filled, dome-shaped, bluish mass with smooth surface measuring around 0.7×1.0 cm on ventral surface of tongue (figure 1). On palpation, it was non-tender, soft, fluctuant and did not blanch on pressure. The clinical characteristics observed lead to provisional diagnosis of congenital mucus retention phenomenon (mucocele). After the medical evaluation, the informed consent was taken from the grandparents and an excisional biopsy was planned under day-care anaesthesia.

On the day of treatment, patient and the parents were invited to the day-stay clinic. Patient was not allowed to eat or drink 6 hours prior to treatment. The inhalation technique was used for sedation. Patient was induced with 2.5% halothane. Anaesthesia was maintained with oxygen, N₂O and halothane. Oxygen saturation and heart rate were monitored continuously. Local anaesthesia (2% lignocaine with epinephrine 1: 80 000) was infiltrated around the lesion. The lip was then everted with digital pressure to increase the lesion’s prominence. An elliptical incision was made with the Bard-Parker blade number 15 attached to a number 3 handle. Stabilising with the tissue holding forceps, the lesion was excised together with the adjacent minor salivary glands up to the underlying muscle layer (figure 2) followed by suturing with 3.0 silk-braided thread (figure 3).

Investigations

The histopathological examination of the soft tissue specimen under H&E-stained tissue sections revealed area of extravasated mucin surrounded by inflamed fibrous connective tissue stroma with overlying parakeratinised stratified squamous epithelium. Mucinophages with nucleus pushed to one side, vascular spaces filled with red blood cells (RBC’s) and salivary ducts lined by cuboidal cells are evident. Connective tissue stroma infiltrated with moderate amount of inflammatory cells chiefly of lymphocytes and lipid-laden macrophages (foam cells) led to the impression of extravasation type of mucocele (figure 4).

Differential diagnosis

The clinical differential diagnosis taken under consideration was oral haemangioma, oral lipoma and soft tissue abscess.

Treatment

After completion of operative treatment under general anaesthesia, the child was transferred to the recovery area for 30 min and then returned to the day-stay clinic where he remained until discharged. Syrups amoxicillin and paracetamol three times a day were prescribed on the first postoperatory day and advised to continue for next 4 days. The sutures were removed on the seventh day with no signs of local haemorrhage or secondary infection, instead only slight inflammation was still present.

Outcome and follow-up

The child was reexamined at periodic intervals of 3 months and 6 months. Postoperatively after 12 months of follow-up, the wound had healed uneventful without any sign of recurrence (figure 5).