Recurrent Postauricular Abscess: A Clue to a First Branchial Cleft Anomaly

Abstract

A 6-year-old girl presented with a painful swelling of 1 week duration in the right postauricular region. Her medical history was significant for recurrent abscesses at the same anatomical site since age 2y, each previously treated with simple incision and drainage (I&D) and systemic antibiotics. On examination, cystic, fluctuant, tender swelling 4cmx2cmx2cm below and behind right ear lobule, pushing the lobule upwards (Figure A). There was no parotid region swelling. Right upper deep cervical and submandibular lymph nodes enlarged, tender.  There was no history of chronic ear discharge or hearing impairment. Contrast-enhanced computed tomography (CECT) of the neck and temporal bone was performed to delineate the extent of the infection and rule out otogenic complications. The scan revealed a well-circumscribed, peripherally enhancing hypodense collection (abscess) in the right postauricular soft tissues seen in intimate superior relation to the right parotid gland, in posterior relation to the right mandibular condyle and in antero-lateral relation to the carotid space. The mastoid air cells were well-pneumatized and clear, effectively ruling out acute coalescent mastoiditis. The patient underwent urgent I&D and antibiotic treatment. Following evacuation of the purulent material, a persistent sinus tract was identified within the abscess cavity. This finding, combined with the history of recurrence, was highly suggestive of a First Branchial Cleft Anomaly. Once the acute infection subsided, the patient is scheduled for formal surgical excision of the tract.