IMMUNOHISTOLOGICAL DIFFERENTIATION OF BENIGN THYROID FOLLICULAR CELL TUMORS FROM MALIGNANT ONES - USEFULNESS OF ANTIPEROXIDASE AND JT-95 ANTIBODIES

An immunohistological investigation using anti-thyroid peroxidase (PO) and JT-95 (JT) antibodies was conducted on surgical specimens of papi llary carcinoma (n = 12), follicular carcinoma (n = 8), follicular ade noma with prominent papillary structure (n = 12), follicular adenoma ( n = 8) and adenomatous goiter (n = 8). In benign lesions, follicle-for ming and papillae-forming epithelia showed positive staining with anti -PO antibody. In 26 of 28 benign lesions, PO-positive areas covered 50 % or more of the cut surface area of the lesions. However in carcinoma s, PO-positive areas were non-existent (13/20) or only focal (7/20) an d the papillae did not stain. The incidence of JT-positive cases was h igher in papillary carcinomas (12/12) than in other lesions (13/36). J T-positive areas were much wider than PO-positive areas in papillary c arcinomas, whereas in benign lesions, PO-positive areas were wider tha n or at least roughly equal to, JT-positive areas. Follicular carcinom as did not stain or stained only focally with these antibodies. In con clusion, these two antibodies seem useful in differentiating benign fr om malignant follicular cell tumors.