Branchial cleft anomalies: a pictorial review of embryological development and spectrum of imaging findings

UNLABELLED: The branchial arches are the embryological precursors of the face, neck and pharynx. Anomalies of the branchial arches are the second most common congenital lesions of the head and neck in children, with second branchial arch anomalies by far the most common. Clinically, these congenital anomalies may present as cysts, sinus tracts, fistulae or cartilaginous remnants with typical clinical and radiological findings. We review the normal embryological development of the branchial arches and the anatomical structures of the head and neck that derive from each arch. The typical clinical and radiological appearances of both common and uncommon branchial arch abnormalities are discussed with an emphasis on branchial cleft anomalies. KEY POINTS: • Anomalies of the branchial arches usually present as cysts, sinuses or fistulae. • Second branchial arch anomalies account for approximately 95 % of cases. • There are no pathognomonic imaging features so diagnosis depends on a high index of suspicion and knowledge of typical locations. • Persistent cysts, fistulae or recurrent localised infection may be due to branchial arch anomalies. • Surgical excision of the cyst or tract is the most common curative option.