The human branchial apparatus is composed of six paired mesodermal arches, separated by endodermal and ectodermal invaginations known as pouches and clefts, respectively . Error in obliteration of a pouch or groove may create a sinus, fistula or a cyst. Approximately 95% of congenital anomalies of the branchial apparatus involve the second arch, pouch or cleft, while the remaining mostly arise from the first and third arches . Fourth branchial involvement is extremely rare with only few cases published in the English literature. In this report we will emphasize the working dilemma in establishing the correct diagnosis of fourth branchial cleft cyst. Diagnostic tools and appropriate treatment will be addressed as well.
Source: Davidi et al.