Estrogen Receptor (ER)- β,But Not ER- α,Is Present in Thyroid Vessels: Immunohistochemical Evaluations in Multinodular Goiter and Papillary Thyroid Carcinoma

Objective: Estrogen receptors (ERs) have been demostrated in the vessel structures of several systems. Little is known on the presence of ERs in the thyroid vessels. Design: We immunohistochemically evaluated both ER-α and ER-β immunoreactivity (IR) in both vascular and follicular thyroid cells in tissue samples from 17 cases of multinodular goiter (MNG) and 17 cases of papillary thyroid carcinoma (PTC). Main Outcome: ER-α IR was undetectable in either tissue examined. In 100% of MNG samples, nuclear ER-β IR was detected in both endothelial and follicular cells. In PTC samples, endothelial nuclear ER-β IR was found in 100% of cases, whereas the nuclear staining of follicular cells was found in 83% of cases. The intensity of staining of the endothelial ER-β IR was comparable between MNG and PTC. However, when follicular cells were considered, a tendency toward a decrease in nuclear staining and a significant increase in cytoplasmic staining were found in PTC lesions as compared to MNG. Conclusions: This study demonstrated that ER-β, but not ER-α, IR is present in the endothelium of thyroid vessels. Furthermore, although data need to be confirmed in larger observations, these results suggest the lack of differences in the pattern of vascular ER-β IR between MNG and PTC.