Complete Branchial Fistula; A Case Report

A case of a 14-year-old boy had a complete type of lateral cervical fistula. The internal orifice of the fistula was recognized at the upper pole of the left tonsillar fossa, and the external orifice was on the skin of the left side of the neck at the level of the cricoid cartilage. To confirm the anatomical location of the fistula, dye staining and fistulography were performed before surgery. These techniques were very helpful as a guide to the surgical removal of the fistula. The fistula was located between the internal jugular vein and the internal carotid artery and crossed over cranial nerves IX and XII, then penetrated the upper pharyngeal constrictor of the tonsil just under the digastric muscle. Histopathological observation disclosed that the lining of the fistula was stratified squamous epithelium, and that the pharyngeal part of the fistula was lined with pseudostratified ciliated cells. Infiltration of lymphocytes and neutrophils was observed in the connective tissue surrounding the epithelial cells of the fistula, and lymphocyte aggregations were seen in the connective tissue. These findings suggest that the fistula was a complete branchial fistula originating from the rupture of the membrane between the 2nd pharyngeal cleft and pouch.