Hyperplastic nodule is characterized by the presence of colloid, predominance of cells located in monolayered sheets and dissociated, and a moderate degree of anisonucleosis. In contrast with the non-tumorous lesion, follicular tumor presents no colloid, predominance of microfollicles and a minimal degree of anisonucleosis.

The ultrasound presentations are also characteristics. The thyroid is composed of multiple nodules is the hyperplastic case while there is a solitary nodule presenting halo sign and perinodular blood flow in the tumorous case.