Branchial pouch sinus tract from the piriform fossa causing acute suppurative thyroiditis, neck abscess, or both: CT appearance and the use of air as a contrast agent

OBJECTIVE. Our objective was to describe the CT appearance of acute suppurative thyroiditis and neck abscess associated with a congenital sinus tract arising from the piriform fossa. In addition, we describe our observations on the use of air as a contrast agent during CT of the pharynx. CONCLUSION, The thyroid is extremely resistant to acute bacterial infection; hence, when such an infection does occur, an underlying anomaly of the thyroid should be suspected, particularly when the infection is recurrent. In such a case, sonography or CT must be used to confirm the diagnosis of acute thyroiditis, neck abscess, or both. Then the sinus tract must be revealed by barium esophagography, CT scanning that uses air as a contrast agent, or endoscopy.