Value of immunoperoxidase staining of thyroglobulin in fine needle aspiration cytology of thyroid diseases

To elucidate the value of thyroglobulin staining by the immunoperoxidase method in fine needle aspiration cytology of thyroid diseases, it was performed on fine needle aspiration smears of 57 cases of various thyroid diseases. Thirteen of 22 cases (59%) with benign nodular goiter were positive. Eight of 14 cases (57%) with papillary thyroid carcinoma were positive. Among these eight cases with positive staining, seven were at clinical stage II or less. Among the other six cases with negative staining, five cases were in clinical stage III or more. There was a significant relationship between clinical stage and thyroglobulin staining (P <.05). One of 10 cases with thyroid cysts was positive. One of four cases with anaplastic carcinoma was positive. One of two cases with follicular thyroid carcinoma was positive. Two cases of subacute thyroiditis were positive. One case of Hashimoto's thyroiditis was positive. Two cases of metastatic thyroid cancer from the ovary were negative. These results reveal that positive thyroglobulin staining was helpful in defining the source of tissue from the thyroid. However, negative staining could not definitively exclude a thyroid origin. Positive thyroglobulin staining in papillary thyroid carcinoma correlated with less advanced clinical stages.