Lymphoepithelial (so-called branchial) cyst within the parotid gland. Report of a case and review of the literature.

A case of a cystic lesion within the parotid gland of a 27-year-old woman is reported. The cyst was surgically removed, taking care not to injure the facial nerve. The histologic picture was in accordance with that of a lymphoepithelial cyst which is also called "branchial cyst". The literature about branchial cysts in the parotid gland is reviewed. The present case was characterized by the inclusion of a small amount of salivary gland epithelium within the cyst wall. A biochemical analysis of the cystic fluid revealed a high amylase activity. From these findings, and those in the literature, it is suggested that the histogenesis of the present case can be explained by the parotid-gland-inclusion theory.