Diagnosis

Thyroid biopsy

Definition - What is a thyroid biopsy?

A thyroid biopsy is a removal of thyroid tissue for microscopic examination. The tissue samples can be examined for any cancer cells, inflammatory cells or antibodies and help diagnose thyroid diseases. In the case of malignant thyroid diseases, they are the means of choice for confirming the diagnosis. It is also known as a fine needle biopsy.

Indication for a thyroid biopsy

A thyroid biopsy is mainly used for tumor diagnosis. As a rule, an ultrasound examination has been carried out on the patient beforehand, which has shown an unclear or tumor-suspicious finding. If the findings in the thyroid gland are unclear, such as lumps in the tissue, tissue samples are taken and examined histologically. As a rule, a cold lump from 1.5 cm is considered suspicious in the ultrasound examination. Cold means that the knot shows no activity. Antibody-producing nodes are accordingly referred to as hot. Microcalcifications in the thyroid gland, which can also be detected by an ultrasound examination, are also considered suspicious and represent a further indication for a biopsy.

also read: Lump in the thyroid gland - is it dangerous?

Preparation before the thyroid biopsy

A thyroid biopsy should usually be preceded by a detailed medical history and physical examination. There should be a definitive indication for the biopsy. If the doctor feels a hard, non-displaceable lump in the patient, an ultrasound examination is carried out in most cases to better assess the lump. If it is cold, hypoechoic nodules more than 1.5 cm in diameter, a biopsy is indicated. Blood is also drawn from the patient. This is done to distinguish hard or soft nodes. The thyroid values (TSH, T3, T4) are examined.
If the indication for a biopsy has been established, the patient is first informed in detail about the upcoming procedure by a doctor. The patient must give his or her signature for consent.

How does the thyroid biopsy work?

A thyroid biopsy, or fine needle biopsy, is a small and uncomplicated examination. It does not require any inpatient stay or anesthesia. It is usually carried out on an outpatient basis.
Once informed, the skin area around the thyroid is disinfected to prevent infections. The ultrasound device is now used to find a suitable location for taking a biopsy. Care is taken to ensure that there are no large blood vessels in the way and that there is enough thyroid tissue. If a suitable spot is found, a puncture needle is used to pierce the skin up to the thyroid gland under ultrasound control. Some tissue is now withdrawn by means of negative pressure in the syringe. This is then placed on a slide. This is followed by another tissue removal. Then the small wound is treated. The examination is hardly painful, similar to taking a blood sample.
The tissue samples are then sent to the laboratory and examined by a pathologist there.

Evaluation of a thyroid biopsy

The tissue samples are evaluated by a pathologist. This examines the cells obtained from the sample for possible malignant characteristics. The result is classified based on the tumor cells found. A distinction is made as to whether tumor cells can definitely be displayed or whether there is still only suspicion. Benign cells can also be found.
In some cases, immunocystochemical staining of the material is also necessary, in which the various components of the sample are colored differently.

A distinction must be made between the following 5 categories when assessing a thyroid tissue sample:

insufficient sample material
Tumor cells not detectable
follicular neoplasia of unclear dignity (changes in the cells can be observed, whereby neither benignity nor malignancy is established)
Suspected tumor cells
Tumor cells are detectable

The clear diagnosis is then made taking into account all examinations (physical examination, laboratory values, biopsy, imaging, etc.).

You can also find out more at:

Thyroid Cancer - What Are The Signs?
Thyroid disorders

When are the results of the thyroid biopsy available?

Depending on the workload of the laboratory, it can take a different amount of time before the result reaches the examining doctor. It is usual about 1-3 working days after the sample is taken. In rare cases, however, it can take up to 2 weeks until the final result is there.

In a personal conversation, the result is discussed with the patient and, if necessary, therapy planning begins.

What are the risks of a thyroid biopsy?

The thyroid biopsy is a low-complication examination. Nevertheless, there may be some risks that the patient must be informed about beforehand.

Possible complications can be:

moderate pain
a swelling in the area where the sample was taken
easy bleeding
rare: infection and inflammation.

Patients taking blood-thinning drugs (called Anticoagulants) should be discussed with the attending physician prior to the procedure. It may be necessary to pause the intake or switch to another drug for a short time to reduce the risk of bleeding.

Is the thyroid biopsy painful?

The examination is rather painless and resembles a blood sample. Anyone who has ever donated blood and been vaccinated knows the slight pain. The examination is so painless that it does not require a local anesthetic.

Duration of the thyroid biopsy

The thyroid biopsy is a very quick test. It usually takes no longer than 15-30 minutes. Usually, however, several appointments are necessary.

If the examination is carried out on an outpatient basis, an appointment is provided for the blood test and information.The tissue is removed the next day and another appointment is scheduled for the personal interview and the communication of the results by the doctor.

What are the alternatives to a thyroid biopsy?

In previous years, tissue samples were taken using a punch or a quick cut in the operating room. However, these interventions came at a higher cost and risk, which means that they are rarely used today. In some cases a sample of the thyroid gland is taken in the operating room if it happens that the thyroid gland is being operated on.

Other alternatives are imaging tests. A good ultrasound can be sufficient for some findings. An X-ray examination or an MRI can also provide information about the tissue of the thyroid gland. In all cases a blood test for thyroid parameters (TSH, T3, T4) should be carried out in order to be able to make statements about the activity of the thyroid gland.
A so-called scintigraphy is also often carried out. Radioactive technetium is injected into the body, which the cells of the thyroid gland absorb. This examination can be used to distinguish between cold and hot nodes. Hot knots have high metabolic activity. They have very many cells, all of which accumulate technetium. According to this, these light up more strongly than cold lumps in the examination.
These are all examination methods that can reinforce the suspicion of a tumor. However, a thyroid biopsy is often the only way to make a definitive diagnosis.

Learn more at:

Thyroid Levels - What Do They Mean?
T4 - thyroxine
TSH

Cost of a thyroid biopsy

The thyroid biopsy is a very inexpensive test. The investigation itself does not require many materials. Since it is now performed routinely, the costs in the laboratory are also low. Exact numbers vary depending on the procedure. However, if the indication is correct, the costs are in most cases covered by the health insurance company.