A Rare Case of Pyriform Sinus Fistula in an Adult.

The pyriform sinus fistula is very rare in adults, and it can present as recurrent deep neck space infection and abscess formation. The fistula results due to failure of obliteration of the third and fourth pharyngeal pouches. The diagnosis is often challenging, even with standard imaging techniques. We present a case of a patient who developed recurrent neck space infection and abscess formation. She was found to have a pyriform sinus fistula with fluoroscopy esophagram, although it was not seen with a standard contrast-enhanced computed tomography scan of the neck.