The lateral cyst of the neck: congenital or acquired?

An outer rim of lymphoid tissue and an inner epithelial lining of squamous composition form the lateral (branchial) cyst of the neck. According to the particular pattern of keratin polypeptides, branchial mass inner lining is shown to be homologous to upper digestive tract (UDT) squamous epithelia. Furthermore, immunostaining of tissue sections with a polyclonal antibody highly specific for the major acidic UDT keratin 13 demonstrates that the epithelium in question is composed of both basal and normally differentiated, i.e. non-keratinizing suprabasal (spinous) cells. 'Import' into a neck lymph node, and rapid growth of oropharyngeal crypt epithelial cells is suggested to initiate a sequence of events leading to an acquired lymphoepithelial mass that may actually present as a 'branchial cyst'.