CEA positivity in tissue and sera of patients with benign breast lesions.

The presence of CEA was studied in paraffin sections of 100 benign breast lesions using an immunoperoxidase technique. In fibroadenomas, CEA was found in 25% of cases as opposed to 64% with cystic disease with or without epitheliosis. Our results demonstrate a tendency for an increased frequency of CEA tissue positivity in association with a more prominent form of epithelial hyperplasia with cystic disease. The observed higher positivity of tissue CEA may reflect a higher 'cellular activity' in the latter lesions compared with fibroadenomas.