HISTOPATHOLOGICAL FEATURES OF ATROPHIC THYROIDITIS WITH BLOCKING TYPE-TSH BINDING INHIBITOR IMMUNOGLOBULINS

To investigate the histopathological features of atrophic thyroiditis (AT) with blocking type-TSH binding inhibitor immunoglobulins (TBII), the present morphological observations were carried out employing addi tional immunohistochemical procedures. Moreover, these were compared w ith examples of goitrous Hashimoto's thyroiditis showing negative TBII (HT). There exist apparent differences between AT and HT. In particul ar, significant follicular atrophy with epithelial flattening includin g decreased positive staining of the follicular epithelial cells for t hyroglobulin in AT was characteristically observed. These results sugg est that the mechanism for the development of hypothyroidism in AT wit h blocking type-TBII might be due to suppression of thyroid cell funct ion through the inhibition of endogenous TSH stimulation by the blocki ng antibody with subsequent epithelial degenerative destruction.