Fig. 3. Schematic, sequential feature of a degenerating nodule corresponding to Fig. 1.

A. An isoechoic nodule is surrounded by a hypoechoic rim (arrow) in the thyroid gland. B. Internal hemorrhage (Hem) compresses the remaining isoechoic solid portion of the nodule (arrows). C. Nodule is gradually contracted with degenerative changes such as fibrosis, infarction, and calcifications.