Immunohistochemical localization of carcinoembryonic antigen in carcinoma in pleomorphic adenoma of salivary gland: use in the diagnosis of benign and malignant lesions.

The localization of carcinoembryonic antigen (CEA) and lysozyme (LZM) was immunohistochemically studied in 34 carcinomas arising in benign pleomorphic adenomas and 25 normal salivary glands in order to assess its potential diagnostic value. CEA in the normal salivary gland was located in luminal cell membranes of intercalated duct cells and serous acinar cells. Strongly positive cell surface and intraluminal staining of CEA appeared in the areas of gland-forming pattern in pleomorphic adenoma. CEA activity was detected in 7/9 cases (78%) of adenocarcinoma, 10/11 cases (91%) of epidermoid carcinoma, 3/8 cases (38%) of anaplastic carcinoma, 5/5 cases (100%) of mucoepidermoid carcinoma, and 1/1 case (100%) of adenoid cystic carcinoma. CEA was always present in the cytoplasm of epithelial cells and luminal contents of neoplastic glands. CEA in epidermoid carcinoma may occasionally react strongly in the cytoplasm. Lysozyme-immunoreactivity was detected in the cytoplasm of intercalated duct cells and serous acinar cells of the normal salivary gland but little or no LZM was observed in any of the tumors. These results suggest that the presence of CEA could be a useful marker that provides valuable information for the differential diagnosis between benign and malignant areas of carcinoma in pleomorphic adenoma of the salivary gland. Moreover, LZM could be of valuable use for discriminating neoplastic from non-neoplastic tissue of salivary glands.