What is a Thyroid Biopsy?

A thyroid biopsy is a medical procedure in which a small section of tissue from the thyroid is removed for examination. Biopsies are commonly ordered to determine the cause of a thyroid nodule, or to research a patient's goiter. Having a request for a thyroid biopsy is not a cause for panic; an estimated 95% of thyroid nodules are benign, so the biopsy is being used primarily for patient safety, to confirm that there is not a cause for concern. If there is a cause for concern, having a biopsy early will increase the probability of a good prognosis.

There are two types of thyroid biopsy. In a fine needle aspiration biopsy, a local anesthetic is used to numb the area, and a needle is inserted and used to pull out a small piece of the thyroid. This tissue can be examined on a microscope slide to see whether or not it is benign. Results from a fine needle aspiration biopsy can include: benign, malignant, suspicious, and nondiagnostic. A nondiagnostic result means that there was not enough tissue to get an accurate analysis.

In an open thyroid biopsy, also called an incisional biopsy, the patient is put under anesthesia so that a doctor can make an incision and actually cut out a piece of a thyroid. This technique is sometimes used when it is suspected that a nodule is malignant, as it allows the doctor to remove the tissue for biopsy while also taking all of the suspected malignant cells out of the body so that they cannot spread.

A fine needle aspiration biopsy usually requires little preparation, and it takes less than an hour. For an open thyroid biopsy, the patient will be asked to take some blood tests to confirm that he or she can safely be anesthetized, and the procedure may require some recovery in the hospital, along with the use of prophylactic antibiotics to prevent infection.

Once the results of the thyroid biopsy are returned to the doctor by the pathologist who examines the tissue, the doctor will call the patient so that they can meet to discuss the results. If the growth is benign, no action will need to be taken. For a suspicious growth, watchful waiting may be advised, while a nondiagnostic result may require a repeat of the biopsy. Malignant growths can be addressed with surgery and treatment for thyroid cancer, which may require consultation with an oncologist.