<prompt> All of following are histomorphological features of Graves disease, except:Symmetrical enlargement of thyroid glandTall and crowded follicular epithelial cellsSmall papillae having fibrovascular core projecting into the follicular lumenPale colloid in the follicular lumen with scalloped margins  <response>: - Papillary formation which lack fibrovascular core is seen in Graves disease - Papillary formation with fibrovascular core is feature of papillary carcinoma of thyroid Graves disease: Most common cause of endogenous hypehyroidism. Caused by autoantibodies against TSH receptor that bind stimulate thyroid follicular cells independent of endogenous trophic hormones. Thyroid gland is usually symmetrically enlarged dt diffuse hyperophy hyperplasia of follicular epithelial cells. Histologically, follicular epithelial cells in untreated cases are tall more crowded than usual. This crowding often results in formation of small papillae, which project into follicular lumen encroach on colloid, sometimes filling the follicles. Colloid within follicular lumen is pale, with scalloped margins. 