Dyshormonogenetic goiter: A morphological and immunohistochemical study

A retrospective morphological and immunohistochemical study of 21 cases of dyshormonogenetic goiter was carried out correlating patterns of hyperplasia and the atypias of the glandular tissues with specific defects in hormonal synthesis, including (1) thyroglobulin synthesis defect (Group I, n = 8); (2) defective organification of iodide (Group II, n = 11); and (3) iodide transport defect (Group III, n = 2). Microfollicular, trabecular, papillary, and oxyphilic cell patterns were more frequent in Group II compared with Group I (Group III was excluded because of the small number of cases). The combined microfollicular and trabecular patterns were more frequently seen in patients in Group II. Two cases of thyroglobulin synthesis defect demonstrated certain morphological specificity characterized by an alveolar pattern. Atypias were more frequent and severe in patients in Group II relative to patients in Group I, but features of malignancy were not found in any patients. Immunohistochemical study using thyroglobulin antiserum demonstrated correlation between morphology and positivity of follicular cells. Scarce C cells were verified in these cases by immunohistochemistry. Using two-paired samples, respectively, of 21 endemic and 21 dyshormonogenetic goiters, we distinguished 85.7% of the cases examined, presented in a double-blind fashion. Scarcity of colloid and prominent cellular atypia were highly suggestive of dyshormonogenetic goiter. Considering the relative rarity of dyshormonogenetic goiter, our studies point out the most common patterns of hyperplasia and atypias in this pathology to avoid misdiagnosis, principally when considering the possibility of malignancy.