Congenital pyriform sinus fistula presenting as a neck abscess in a newborn: A case report.

Rationale: Congenital pyriform sinus fistula (CPSF) is a branchial abnormality originating from the third or fourth branchial pouch and is an important cause of anterior cervical abscess in children. Here we present a case of neck abscess in a newborn that was diagnosed as CPSF. Patient concerns: A male infant with a birth weight of 3660 g was admitted to hospital 25 minutes after birth after discovery of a cystic mass with extensive skin swelling in the left side of the neck. B-mode ultrasonography of the left neck showed an anterior cervical cystic mass of indeterminate nature. Diagnosis: Congenital pyriform sinus fistula. Interventions: The neck abscess was incised and drained under general anesthesia. Examination under suspension laryngoscopy revealed a pyriform sinus fistula. Laser cauterization was performed simultaneously. The wound was dressed and anti-inflammatory treatment was provided. Outcomes: The neck wound healed uneventfully. After 3 months, the fistula was confirmed to be closed by laryngoscopy under general anesthesia. No recurrence was detected during 9 months of follow-up. Lessons: CPSF should be strongly suspected in a patient with an unexplained neck abscess or recurrent acute suppurative thyroiditis, especially on the left side.