[Fistula of the 4th endo-branchial pouch. Apropos of 4 cases].

The congenital fistula of the piriform sinus is a rare, often overlooked, malformation originating in the branchial pouch. More than 70 observations have been reported in the literature. The authors describe four new cases of documented fistula of the fourth endobrachial pouch. The terminology of these malformations and the different hypotheses concerning the fistular routes is given. The authors discuss their own observations and those reported in the literature in order to better define the clinical diagnosis and the request for complementary examinations for fistulae of the piriform sinus. Surgical exploration is the ultimate diagnostic and therapeutic step.