A thyroid biopsy is a procedure in which a small sample of tissue is removed from the thyroid gland and looked at under a microscope for cancer, infection, or other thyroid problems. The thyroid gland is found in front of the windpipe (trachea), just below the voice box (larynx).
A sample of thyroid tissue can be taken by:
Fine-needle biopsy. Your doctor puts a thin needle through the skin and into the thyroid gland. Many thyroid specialists like to use a needle biopsy method rather than surgery.
Open biopsy. Your doctor makes a cut (incision) through the skin to see the thyroid gland. This method is done when other tests have not found the cause of your symptoms.
Core needle biopsy. Your doctor inserts a needle with a special tip and removes a sample of tissue about the size of a grain of rice.