Tissue Polypeptide Antigen Immunostaining in Fine Needle Aspirates from Solid Breast Nodules

: The purpose of this study was to determine the role of Tissue Polypeptide Antigen (TPA) immunostaining in the evaluation of aspiration smears from solid breast nodules and to discuss its possible clinical applications. Seventy-one cytologic specimens were studied; 52 were carcinomas, 15 fibroadenomas and 4 fibrocystic dysplasia. TPA was visualized with the peroxidase-antiperoxidase method, using 3-3' diaminobenzidine as chromogen and hematoxylin as counterstaining. The incidence of TPA-positive aspiration smears was 88.5% in the carcinomas and 26.7% in the fibroadenomas. The four cases of fibrocystic dysplasia showed variable behaviour. The intensity of the TPA staining varied from - to and was most frequently high in the carcinomas. The results of this research show a good correlation between a diagnosis of carcinoma and TPA positivity in fine needle aspirates of solid breast nodules.