Neck abscess associated with a piriform fossa sinus tract in an adult.

Perithyroidal inflammatory masses deriving from developmental remnants of the 3rd and 4th brancial pouches are rare. We report a case of an otherwise healthy 31-year-old man, who presented with fever and swelling of the left side of the neck. Neck ultrasound showed a displaced left thyroid lobe with induration of the strap muscles. Fine-needle aspiration biopsy revealed pus, positive for Staphylococcus aureus species. Antibiotic treatment led to rapid clinical improvement and reversal of imaging features, without the need for surgical intervention. This rare clinical entity should be always considered in the differential diagnosis of an inflammatory neck mass.