A case of branchial cyst suggesting the first branchial cleft origin

Anomalies of first branchial cleft are rare lesions that were classified as two types by Work. Type I incorporates ectodermal elements from the first branchial cleft only. Type if incorporates ectodermal elements from the first branchial cleft and mesodermal elements from the first and second branchial arches.We experienced a Type II anomaly of first branchial cleft occurring in an 8-month-old infant. The sinus was located anterior to the right sternocleidomastoid muscle and opened at the right submandibular region through a fistulous tract. Histopathologically the sinus and tract wall was lined by keratinized squamous epithelium with adenexal skin structures and cartilage components. However, we also observed peudostratified ciliated epithelium with lymphoid tissue in part of sinus and tract wall. This finding suggested that this anomaly originated from not only first branchial cleft but second branchial cleft.