ABSTRACT
The aim of this study was to determine the value of the argyrophilic nucleoli organizer region [AgNOR] as a proliferative marker in neoplastic and non-neoplastic lesions of the thyroid i-r Methods: AgNOR count was evaluated in paraffin. Embedded tissue of resection specimens of the thyroid from 100 patients was retrieved from files of the Pathology Department of the Ghaem Hospital Medical Center including: Normal thyroid gland [N = 8] Nodular Goiter [N=19] Follicular Adenoma [N = 34] Follicular carcinoma [N=10] Medullary carcinoma [N = 4] Papillary carcinoma [N = 15] Anaplastic carcinoma [N = 4] Thyroiditis [N = 6] The investigated parameters included the number, size, shape and localization of AgNOR dots in nucleoli of hundred cells and percentage of nucleoli with at least 3 and 5 or more AgNOR dots per cell [distribution score]. The mean AgNOR dots and 3- dot per cell were statistically significantly higher in malignant lesions in comparison to benign lesions. No clear separation statically between groups about parameter 5 or more dots per cells. Total discrimination between follicular adenoma and carcinoma was achieved by quantification of AgNOR dot tumor nucleolus cell [AgNOR distribution score]. The AgNOR and AgNOR distribution score proved to be the most valuable diagnostic criterion for the differentiation between follicular adenoma and carcinoma of the thyroid