Cystadenolymphoma of the parotid gland an immunohistochemical study of the epithelial component of twenty cases.

Carcinoembryonic antigen, epithelial membrane antigen, Keratin, Desmin, Vimentin, CD30, lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, S-100 protein, somatostatin and glucagon were looked for using immunohistochemical methods in the epithelial component of 20 parotid gland cystadenolymphomas and 20 normal parotid glands. Carcino-embryonic antigen, ephithelial membrane antigen, S-100 protein, and somatostatin were found in the epithelial cells of most of the cystadenolymphomas. In normal parotid tissue, carcinoembryonic antigen, epithelial membrane antigen, Keratin, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and S-100 protein were found in all three types of ductal cells, somatostatin only in intercalated and striated ductal cells, and lysozyme only in acinar and intercalated ductal cells. Desmin and CD30 were found in the epithelial component of seven of the 20 tumors versus none of the 20 normal parotid glands. Glucagon and Vimentin were negative both in tumor epithelial cells and in normal parotid ductal cells. Our results support the theory that cystadenolymphomas arise from epithelial cells. The presence of lysozyme in the epithelial tumor cells and in the intercalated ductal cells of normal parotid tissue suggest that cystadenolymphomas may arise from the intercalated ducts. The presence of S-100 and somatostatin may indicate that the tumor derives from neuroendocrine structures, but further studies are needed to clarify this point.