Squamous Cell Carcinoma in Branchial Cleft Cyst
The lining of branchial cleft cysts and fistulous tracts usually consists of squamous epithelium or ciliated columnar epithelium. Lymphoid tissue with germinal centers is present beneath the epithelium. Cysts located in the lower neck may contain serous, mucinous, or sebaceous glands. Secondary bacterial infection and the development of squamous cell carcinoma (shown here) are rare complications.