Ploidy level and proliferative activity measurements in a series of 407 thyroid tumors or other pathologic conditions

This study describes the ploidy level and proliferation rate in a series of 74 multinodular goiters (MNGs), 17 cases of Hashimoto's disease, 33 cases of Basedow's disease, 113 adenomas, 139 primary carcinomas, and 31 cervical lymph node metastases from 376 patients. Both ploidy level and proliferation rate were assessed by digital cell image analyses of Feulgen-stained nuclei from formalin-fixed, paraffin-embedded tissues. The ploidy level of each sample was assessed using both its DNA index and its DNA histogram type. The proliferation index assessments corresponded to the determination of the proportion of cells in the S-phase fraction. The data reveal that the proportion of aneuploid cases increases according to the following sequence: simple MNGs and normomacrovesicular adenomas-->MNGs with adenomatous hyperplasia and microvesicular adenomas and Hürthle cell adenomas-->papillary and Hürthle cell carcinomas-->follicular and medullary carcinomas-->anaplastic carcinomas. This suggests the preneoplastic nature of the microvesicular adenomas and even of MNGs with adenomatous hyperplasia. The ploidy levels of 99% of the 407 cases of the thyroid tumor series could be described using six DNA histogram types: diploid, hyperdiploid, triploid, hypertriploid, tetraploid, and polymorphic. It was possible to assess the proliferation rate of 279 samples. The results show that a significantly higher proportion of malignant compared with benign thyroid tumors (35.5% v 10.5%, respectively) exhibited a proliferation index higher than 5%, and that, whether benign or malignant, the hypertriploid thyroid tumors proliferated significantly less than the nonhypertriploid thyroid tumors.