[Recurrent thyroid abscess in children and malformations of the pyriform sinus].

Recurrent "abscesses" occurring in the thyroid area in children are due to branchial anomalies. Their origin is located close to the oesophageal inlet at the apex of the lateral hypopharyngeal process: the pyriform sinus. The key for the diagnosis comes from laryngohypopharyngoscopy. The true original anomaly is a controversial topic: the persistence of a canal originating from the 3rd or 4th branchial pouch. Anyhow, these anomalies sometimes build tracts or cysts in the deeper parts of the neck, down to the supraclavicular or thoracic areas. Most often, they are limited to the soft tissues surrounding the left thyroid lobe. In these cases, no cyst wall can be found. The 3 cases reported here allow us to ascertain that a pharyngeal infection is the trigger for the neck abscess. Furthermore, a mucosal opening can be the only found anomaly. After recovery from the infectious process, these anomalies have to be treated by a mucosal suture of the pyriform sinus. The recurrent laryngeal nerve should be first discovered and the removal of a small piece of cartilage can be required. If these diagnostic and therapeutic procedures are used at the first infectious episode, they may prevent the occurrence of repeated thyroid "abscesses" in children.