Retropharyngeal Abscess as the Initial Presentation of a Third Branchial Cleft Anomaly: A Case Report

Abstract

Objectives: To describe a rare case of a retropharyngeal abscess revealing an infected third branchial cleft fistula in a 5-year-old child, with emphasis on the clinical presentation, radiological findings, surgical management, and the importance of considering branchial cleft anomalies in children presenting with deep neck infections. Case Report: A 5-year-old boy was admitted with left lateral cervical swelling associated with neck stiffness, persistent fever, and dysphagia lasting one week. Physical examination revealed a hard, tender left lateral cervical swelling measuring approximately 4 cm, associated with torticollis. CT imaging demonstrated deep cervical soft-tissue thickening and infiltration, with widening of the retropharyngeal space caused by a 35 × 14 × 30 mm collection and inflammatory extension into the adjacent tissues. Incision and drainage were performed through a left lateral cervical approach. During the same surgical procedure, direct laryngoscopy revealed erythematous hypertrophy of the left posterior pharyngeal wall. An abnormal opening was also identified in the left pyriform sinus. Discussion: A retropharyngeal abscess secondary to an infected third branchial cleft fistula is an extremely rare condition. Diagnosis can be challenging because the initial presentation may mimic a primary retropharyngeal abscess. Flexible laryngoscopy may fail to identify the internal opening because of mucosal redundancy, whereas direct laryngoscopy allows visualisation of the pyriform sinus opening and identification of the fistulous tract.