Branchial cyst in a heifer.

A branchial cyst in a heifer was removed surgically. Diagnosis was based on clinical signs, analysis of cyst contents, and histologic examination of the cyst wall. Biochemically, the cyst fluid resembled a transudate. The cyst lining consisted of nonciliated, pseudostratified columnar epithelium and pigmented, keratinized, stratified squamous epithelium. The embryologic origin was thought to be endoderm of the 2nd pharyngeal pouch and adjacent ectoderm.