Background: Third and fourth branchial remnants (pyriform sinus) may result in cysts or abscesses that are in close contact with the thyroid gland. These anomalies are rare and often present diagnostic
and therapeutic challenges.Case Report: The charts of patients treated with a branchial cysts between 1994 and 2002 at the Department of Pediatric Surgery were reviewed for identification of pyriform sinus cysts. Inclusion factor was thyroid and/or thymic tissue in the wall of the cyst identified in the histological examination. Clinical presentation, imaging, treatment and outcome were recorded. Four newborns, three girls and one boy, ranging in age from 3 to 13 days were identified. Primary symptoms were painful swelling of the neck, asymptomatic cervical mass, stridor and respiratory distress. Barium swallow was performed in 2 patients with one positive result.CT scan was diagnostic in all children. All patients underwent successful cyst excision. Two underwent simple excision of the cysts. One had repeated incision and drainage and in one patient the infection was treated temporarily by needle aspiration and antibiotics before excision. No recurrence was observed.Conclusions: Diagnosis requires a high index of suspicion, both from the clinician and the radiologist. All pyriform sinus cyst presented as left sided neonatal cervical mass. US is first performed, complemented by CT scan if the diagnosis is not clear. A simple incision and drainage for infected patients during the neonatal period with subsequent surgical removal is recommended. Thyroid and/or thymic tissue in the wall of the cyst is identified in the histological examination.

Keywords: lateral cervical cysts, pyriform sinus, branchial remnants, neonate, Surgery