Can thyroid nodules shrink?

Yes.: Most thyroid nodules remain stable over many years. Some can increase in size and some can decrease. It depends on the composition of the nodule.

Nodules shrink: Thyroid nodules can both grow and shrink. Generally the grow over the course of time.

They can.: Nodules caused by inflammation (thyroiditis) can shrink, or even disappear entirely, when the inflammation resolves. Cystic nodules (fluid filled areas) can shrink if the fluid is reabsorbed by the surrounding tissue. Most nodules, however, either remain the same size they were when discovered, or continue to enlarge.

Very unlikely: Thyroid nodules either stay the same or grow. I have never seen one shrink on its own.