Apparent lack of usefulness of monoclonal antibody Ki-67 in thyroid tumour pathology. Relation to histological typing and classification.

In order to test its potential application to thyroid tumour pathology, the monoclonal antibody Ki-67 was used to demonstrate immunohistochemically proliferating cells in 31 non neoplastic and neoplastic lesions of the thyroid. Twenty benign lesions were negative. Of the 11 malignant tumors, 4 papillary, 2 follicular and 1 medullary carcinomas were also negative; only 3 follicular and 1 medullary carcinomas were positive. Moreover, no correlation was found between Ki-67 immunostaining status and histological typing or pTNM pathological classification in the 11 malignant tumors.