The thyroid is a gland in the lower neck that regulates heart rate, blood pressure and food-to-energy conversion by making and secreting certain hormones. These hormones are important for cell growth and chemical reactions within the body. Several things can alter the productivity and effectiveness of this gland, including hypoechogenic thyroid lesions. Giving these specific lesions swift medical attention is essential to your health.
Nodules or Lesions
A thyroid nodule or lesion is typically a small fluid-filled or hardened lump which forms in the thyroid. Lesions are usually too small to notice without a doctor's examination, but in some cases, they may become so large that they are visible to the naked eye or obstruct the windpipe. These nodules are rarely cancerous, but a fast-growing lesion may be a sign of malignancy. To test for cancer, a doctor will commonly order an ultrasound of a thyroid lesion which determines the echogenicity of the nodule. A nodule can be hypoechogenic, hyperechogenic or normal (normoechogenic).
The ultrasound test is painless and usually takes only around 10 minutes. A doctor rubs lubricant jelly on the neck and passes a transducer over the nodule. The ultrasound sends sound waves through the skin, which then bounce back to the transducer and create an image of the lesion. This test is performed to determine whether the lesion is hyperechogenic, hypoechogenic or neither. The echogenicity of the thyroid refers to the number of sound waves that are reflected back to the transducer compared to the number of waves reflected back by other structures in the neck.
The thyroid gland is usually more echo-dense than the tissues and structures surrounding it because it contains iodine. If the thyroid nodule sends back fewer waves than nearby structures, it is hypoechogenic. If it sends back more waves, it is hyperechogenic. Because thyroid lesions are so rarely cancerous, both hypoechogenic and hyperechogenic results usually turn out to be benign, but a hypoechogenic result can mean a greater possibility of complications.
Hypoechogenicity and Hypothyroidism
In a study by Kuma Hospital in Japan, doctors discovered that patients with hypoechogenic thyroid lesions are six times more likely to develop hypothyroidism than people with hyper or normoechogenic lesions. Hypothyroidism is the medical term for an underactive thyroid, which can cause dangerous health problems, such as obesity and heart disease, if left untreated. Patients with hypothyroidism may feel sluggish, constipated, have a pale pallor, or experience muscle aches, heavy menstrual periods and depression. Advanced hypothyroidism is referred to as myxedema and may be life-threatening.
Doctors have found a higher incidence---about 26 per cent---of malignancy in hypoechogenic nodules than in hyperechogenic ones. However, while hypoechogenicity is cause for more alarm, the ultrasound is not necessarily an accurate diagnostic tool for cancer. Doctors will typically order more tests of hypoechogenic lesions to get clear results. One such test is the fine-needle aspiration (FNA) biopsy, in which a doctor removes a sample of cells from the hypoechogenic lesion and sends it to a lab for cancer testing.