Histological and functional correlation of thyroid carcinoma by immunohistochemistry.

40 cases of thyroid carcinoma comprising of 22 follicular, 11 papillary, 4 medullary, 2 anaplastic and 1 medullary carcinoma with focal areas of papillary differentiation were selected for this immunohistochemical study for the presence of thyroglobulin, calcitonin and somatostatin. As per the functional classification recommended by Otto L Jungberg, 22 cases were well differentiated, 13 were of intermediate differentiation with 3 poorly differentiated cases. 2 cases of anaplastic carcinoma were negative for all the 3 markers. Correlation between functional classification and histological pattern show 77% of the well differentiated type to be of follicular pattern with the rest consisting of papillary carcinoma. In the intermediate type 38.4% were follicular carcinoma, 15.3% medullary carcinoma and the rest, papillary carcinoma. Poorly differentiated type consisted of 2 medullary carcinomas. Contrary to previous reports, functional differentiation did not always correlate with histological pattern.