Imaging findings in acute neck infection due to pyriform sinus fistula.

INTRODUCTION Pyriform sinus fistula is a congenital branchial pouch abnormality that is often overlooked as a cause of acute neck infection in children. Our aim is to demonstrate the value of various imaging modalities (ultrasound, computed tomography [CT], barium oesophagraphy) in its diagnosis. MATERIALS AND METHODS The preoperative imaging findings of 5 patients with surgically proven pyriform sinus fistula who presented with acute neck infection between September 2001 and March 2003 were retrospectively reviewed. CT was performed in all patients, 4 patients had barium oesophagraphy and 3 had an ultrasound scan. RESULTS All 5 patients suffered from upper respiratory tract infection within a week of developing a tender swelling on the left side of the neck. Four patients had a history of recurrent neck infections. CT depicted inflammation of the left perithyroid soft tissue and adjacent left thyroid lobe in every case. In 2 cases, CT demonstrated the presence of a pyriform sinus fistula. Ultrasound, performed in 3 patients, correlated strongly with the CT findings. It also showed gas within a fistula in 1 case. Barium oesophagraphy clearly delineated the fistula in 3 out of 4 cases. CONCLUSION Ultrasound and CT accurately showed the presence of acute neck infection and could demonstrate the pyriform sinus fistula. Barium oesophagraphy most clearly depicted the presence and course of the fistula. Recurrent left-sided neck infection in a child should alert the physician to the possibility of an underlying pyriform sinus fistula and imaging should be performed to confirm its presence.