Thyroid abscess with branchial anomaly

The third arch branchial fistula is a rare congenital abnormality that presents as an inflammatory process in the anterior neck, often in the region of the left lobe of thyroid. Incomplete fistula is not an uncommon finding extending from base of pyriform sinus to the thyroid or perithyroidal space, which predisposes to recurrent suppurative thyroiditis during episodes of upper respiratory infection. Complete fistula of third arch is extremely uncommon, especially of congenital origin. A 10-year-old male child presented with a small opening in the anterior neck since birth, with a swelling around it. Computerized tomography revealed a patent tract from neck skin to base of pyriform sinus. Total excision of the tract up to the left pyriform sinus with hemithyroidectomy was performed. There was no recurrence at 22 months of follow-up.