Is it true that the majority of thyroid nodules are hypoechoic and although thyroid cancer is usually hypoechoic, most hypoechoic nodules are benign?

Thyroid nodules: Yes, that is true. Sometimes a nuclear thyroid scan is helpful to determine hot (benign) nodules vs cold (sometimes malignant) nodules. I'm sure you can request that test for clarity.

Size?: It is correct that in younger people thyroid nodules are benign, however, us is not very good at ruling out malignancy. Close follow up of the nodule is needed with us every 6 months. If the nodule is larger than 1 cm, fine needle aspiration biopsy needs to be considered.