Pyogenic thyroiditis due to branchial pouch sinus.

Suppurative thyroiditis due to branchial pouch sinus is a rare disease, affecting children and young adults. It presents as an abscess in the lower lateral neck, usually on the left side. Suppurative thyroiditis can be suggested by ultrasound, radionuclide scintigraphy or CT scan, but the diagnosis can only be established by barium swallow showing the sinus from the apex of the pyriform sinus to the perithyroid region. Complete surgical excision of the sinus is essential. Two patients are presented and the role of the various imaging modalities in the diagnosis is discussed.