Follicle structure-dependency of thyroglobulin and thyroxin staining in the thyroid glands of Graves' disease

H.E. morphology of the thyroid glands from 170 patients with Graves' disease was studied, and the thyroid follicles were classified into two main groups: (1) F pattern, in which the follicles show circle/ellipse on cut sections; (2) P pattern, in which the follicular epithelium protrudes into the lumen or a follicle, is accompanied by proliferation of tubular or microfollicular structures. Studies on three serial sections of 88 thyroid glands stained with hematoxylin and eosin, thyroglobulin (TG), and thyroxin (T4), respectively, revealed the followings: (i) TG/T4 staining is dependent on the follicle structure (i.e., F or P); while the epithelium and colloid including scalloped vesicles in F follicles generally exhibited a direct relationship between TG and T4 staining, those in P follicles often showed an intense TG, but negative T4 staining. (ii) The results of morphological and immunohistochemical studies of P follicles among the cases are consistent with the view that P follicles are in the process of proliferation of immature daughter follicles from a main follicle and of their maturation. (iii) P follicles of Graves' thyroid glands were evaluated as possible non-neoplastic counterparts of well-differentiated follicular and papillary tumors.