Abstract
Branchiogenic fistulas are congenital alterations that affect the cervical compartments. Those of the fourth branchial cleft are rarest and can begin late with very serious complications. The suppurative thyroiditis can be a complication of these alterations. We describe a case of 3-year-old girl with high fever, left cervical swelling and increased inflammation indices. The neck ultrasound showed an abscess of the left thyroid lobe and a fluid mass with aerial content in laterocervical region. On MRI, the fluid mass extended from the left piriform sinus to the mediastinum. Fluoroscopy also highlighted a fistolose trait that extended from the left side wall of the esophagus, anteriorly towards the trachea. Treatment of these pathologies must be early and a late diagnosis can put patients' lives at risk.