Graves' hyperthyroidism. - Figure 6. Cytological features - pleomorphism.

Pleomorphism, i.e. irregularly shaped nuclei is an infrequent finding in Graves' disease except for patients after radioiodine therapy. Plemorphic cells displaying degenerative changes (first row of images) cause little differential diagnostic problem. The finding of intact pleomorphic nuclei (images in the second row) in the absence of other cytological signs of a thyroid tumor is not enough to raise the suspicion of carcinoma.