[Recurrent pseudothyroiditis and cervical abscess. The fourth branchial pouch's role. Apropos of 16 cases].

Among the causes of inflammatory swelling of the neck in children, the "cysts" and ducts joining in the hypopharynx deserve being individualized. This unrecognized pathology is indeed responsible for suppurative pseudothyroiditis or cervical abscesses relapsing in spite of adequate antibiotic treatment and incision-drainage. X-ray films may help as they often show the fistula. Diagnosis relies on hypopharyngoscopy. This investigation only may assess the origin of this "internal fistula" by showing the mucous opening of the bottom of the pyriform sinus, from which sometimes springs some pus when pressing the neck. The clear left predominance of this canal and its junction between the superior and inferior laryngeal nerves suggest that its origin could be the 4th branchial pouch. Its treatment consists of complete surgical excision, which avoids relapses.