Histology of Graves' Disease – High-power The histological appearance of the thyroid in Graves' disease consists of tall columnar epithelium and scalloping of the colloid (Fig. 17.23a), with varying degrees of lymphocytic infiltration. Fig. 17.23a Histology of thyroid tissue in Graves' disease. A high-power view showing tall, unfolded columnar epithelium, together with scalloping of follicular colloid. (Haematoxylin and eosin staining of a tissue section that is 5µm in thickness, taken from a routinely formalin-fixed and paraffin-embedded subtotal thyroidectomy specimen.)