A rare case of deep lobe parotid sialocele in a paediatric patient

A 12-year-old male presented to the pediatric outpatient department with a history of progressive swelling on the left side of the neck, particularly in the mandibular region, for the past five to six months. The swelling was gradual in onset, non-painful and not associated with fever, dysphagia or any discharge. There was no history of trauma, infection or previous surgery in the region. On examination, a well-defined, soft, cystic and non-tender swelling was noted over the left parotid and upper cervical region. The overlying skin was normal without signs of inflammation. No regional lymphadenopathy was appreciated. Intraoral and oropharyngeal examinations were unremarkable, and there was no deviation of the tongue or trismus. Magnetic resonance imaging (MRI) of the neck (plain and contrast) revealed a well-marginated multiloculated cystic lesion involving the deep lobe of the left parotid gland, measuring approximately 6.5x4.8x1.8cm. The lesion appeared hypointense on T1WI (A) and hyperintense on T2WI (B), with multiple thin internal septations and mild intracystic nodularity. No diffusion restriction was observed, and there was no intralesional enhancement on post-contrast imaging (C). The lesion displaced the left submandibular gland anteroinferiorly, extended medially into the carotid space with preservation of major neck vessels and reached posteriorly up to the posterior cervical space. The thyroid gland, larynx, pharynx and major vascular structures appeared normal. Based on clinical and imaging findings, a diagnosis of sialocele involving the deep lobe of the left parotid gland was made. Sialocele arises secondary to ductal disruption or obstruction of the salivary gland.