PAEA Surgery End Of Rotation (EOR) Practice Exam

What happens to up to half of benign thyroid nodules when thyroid hormone is administered?

1. They grow larger

2. They remain unchanged

3. They become malignant

4. They disappear

The correct answer is: They disappear

When thyroid hormone is administered to individuals with benign thyroid nodules, a significant number of these nodules can undergo a reduction in size or even disappear entirely. This phenomenon is primarily due to the suppression of thyroid-stimulating hormone (TSH), which is a key growth factor for many thyroid nodules. When TSH levels decrease as a result of exogenous thyroid hormone therapy, the stimulus for the growth of benign nodules diminishes, leading to regression. This occurrence highlights the physiological relationship between TSH and thyroid nodules, where higher TSH levels may promote growth, and lower TSH levels can result in atrophy or shrinkage of nodules. It's imperative to understand that this effect is typically seen in benign nodules and does not apply to malignant nodules, which may not respond in the same manner. The other options provided do not accurately reflect the common clinical outcomes following thyroid hormone administration. The growth of nodules or their transformation into malignancy would not be expected responses to such treatment under normal circumstances. Thus, the correct answer underscores the significant reduction or disappearance of benign thyroid nodules upon administration of thyroid hormone.