QUIZ: No. 39, 2025

 CP & USG

MRI

Findings: A swelling is seen around the angle of mandible on left side, with a pit. Ultrasound images show a hypoechoic tract coursing through the substance of superficial lobe of left parotid gland. It courses through the subcutaneous plane and reaches the skin surface. MRI images show a T2W and STIR hyperintense, T1 hypointense tract coursing through the superficial lobe of left parotid gland, reaching the skin surface. Cranially, it is blind ending, reaches upto external auditory canal.

Diagnosis. First branchial cleft sinus

·      First branchial cleft anomalies are rare, comprising ~7% of all branchial cleft anomalies.

·      They arise from incomplete fusion between the first and second branchial arches.

·      They are located within or adjacent to the parotid gland and may present as a cyst, sinus, or fistula.

·      They communicate either with the external auditory canal (EAC) or with the skin of the upper neck.

·      Recurrent discharge or infection is common. Facial nerve involvement may occur in large or inflamed lesions.

·      Imaging is crucial to delineate the tract, its cranial extent, and proximity to the facial nerve, guiding safe surgical excision.

·      Definitive treatment: Complete excision of the tract; meticulous dissection required to prevent facial nerve injury.