Background:    The objective of this study was to evaluate the presence of estrogen receptors (ER) alpha and beta in various thyroid lesions and to assess the practicality of this test.
    Material/Methods:    Immunohistochemical stains were performed for both ER alpha and ER beta, for evaluation of immunoreactivity in 296 thyroid tissue samples that consisted of 150 goiters, 90 papillary carcinomas, 19 follicular adenomas, 15 Hurtle cell adenomas, 6 Hashimoto thyroiditis, 5 anaplastic carcinomas, 4 medullary carcinomas, 4 follicular carcinomas, 2 Hurtle cell carcinomas, and 1 squamous cell carcinoma of the thyroid. Three variables were evaluated in each sample: The intensity of the staining both nuclear (1) and cytoplasmic (2), and the spread of the stain over the sample (3).
    Results:    None of the histologic samples showed immunoreactivity for ER alpha. Positive immunoreactivity results for ER beta were found in tissue samples from all of the different groups of diagnoses, both benign and malignant lesions as well as in normal thyroid tissue. No significant difference was found between the various thyroid lesions.
    Conclusions:    The study shows that ER beta is the only ER detectable in thyroid tissue. However, ER beta expression has no significant specifications for differentiation between benign and malignant lesions of the thyroid. ER alpha is undetectable in the thyroid. Further investigations are necessary mainly in the laboratory immunohistochemical workup.

Keywords: Goiter, Nodular - pathology, Estrogen Receptor beta - metabolism, Estrogen Receptor alpha - metabolism, Breast Neoplasms - pathology, Adult, Thyroid Gland - pathology, Thyroid Neoplasms - pathology