RESUMEN
Fine-needle aspirates and paraffin-embedded tissue sections from 91 cases with diverse breast diseases were immunostained with carcinoembryonic antigen (CEA) monoclonal antibody using a BioGenex StrAviGen kit based on the biotin-streptavidin amplified methodology. The results were compared with histopathologic tumor type and tumor stage. CEA was not expressed in fibrocystic changes with mild or florid epithelial hyperplasia (n = 23) and fibroadenomas (n = 8). On the other hand, 90% (56/60) of primary breast carcinomas showed positive cytoplasmic staining for CEA. No correlation was found between CEA expression, histopathologic tumor type, and tumor stage. We suggest that CEA immunocytochemistry will help in the accurate diagnosis of primary breast carcinoma in fine-needle aspirates in addition to the usual cytological criteria.