Hypoechoic nodules are growths on the thyroid that produce weak echoes when a sonogram is used, according to EverydayHealth. Although this can denote a cancerous growth, most often hypoechoic nodules are benign.
When tested with a sonogram or ultrasonography, thyroid nodules can either be hyperochoic or hypoechoic, explains EverydayHealth. Hyperechoic nodules produce echoes when a sonogram is used, suggesting that the mass isn't solid, but cystic. Hypoechoic nodules produce weak echoes, meaning that the nodules are solid and, in some cases, filled with a cancerous mass or tumors, says the American Thyroid Association. Hypoechoic nodules that are at least 1 centimeter wide need to be biopsied and tested for malignancy.
If a physician finds a suspicious hypoechoic nodule in need of further investigation, he performs a fine needle aspiration, states EverydayHealth. He inserts a needle into the nodule and removes some of the cells, so they can be examined underneath a microscope. While almost half the population have thyroid nodules, only about 5 percent are cancerous, points out the American Thyroid Association. Often, cancerous thyroid nodules appear speckled or flecked with white on the ultrasonography. These spots are calcium deposits called microcalcifications and occur in less than half of cancerous nodules.
Large nodules can require surgical removal even if they are benign, either because they cause discomfort in swallowing or because they produce hormones, according to Everyday Health.