Thyroid biopsy – indications, preparation, complications, price. When to do and how is it done?

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A thyroid biopsy is a specialized invasive test. This form of diagnosis is needed primarily when a thyroid nodule is detected. The test involves taking a section from the thyroid nodule, which is then sent for laboratory tests. The primary method of examination is fine needle biopsy (BAAC). If necessary, a core needle biopsy is also performed.

What is a thyroid biopsy?

A thyroid biopsy is a test that analyzes nodular changes in this organ. Performing a biopsy is always preceded by other diagnostic procedures, primarily palpation and ultrasound of the thyroid gland. Sometimes a disturbing change is also detected during computed tomography or magnetic resonance imaging.

There are fine-needle biopsy and coarse-needle biopsy. Both methods involve taking a section of the changed tissue with a needle. The sample obtained in this way is subjected to a laboratory test. In this way, neoplastic or inflammatory changes of a different nature are detected.

Fine needle biopsy of the thyroid gland – indications

Fine needle biopsy of the thyroid gland (to be exact – targeted fine needle aspiration biopsyor FNAB) is most often needed when at least one thyroid nodule is detected. The indications for its implementation may be the feeling of the presence of a nodule within the parenchyma of the gland, enlargement of the thyroid gland associated with pain when touching it, multinodular goitre, as well as ultrasound detection of lesions greater than 1 cm in diameter, hypoechoic changes and the presence of vaguely delineated from the parenchyma of the thyroid nodules.

Recommendations for fine-needle biopsy also appear when the risk of malignant changes is increased:

1. the patient belongs to the risk group – there have been cases of thyroid cancer in his family or genetic tests have confirmed mutations in specific genes (eg RET);
2. a lump larger than 4 cm;
3. disturbing structure of the tumor, e.g. hard or growing rapidly;
4. enlarged lymph nodes;
5. ultrasound image showing changes such as microcalcifications or tissue infiltration;
6. iodine deficiency in the patient;
7. exposure of the patient to ionizing radiation (e.g. undergoing radiotherapy).

If the FNAB is inconclusive and there is a suspicion of changes in the thyroid gland, your doctor may recommend a core needle biopsy.

1. Also read: Thyroid cancer. What do you need to know?

Core needle biopsy of the thyroid gland – indications

Core needle biopsy (BG) of the thyroid gland is an auxiliary diagnostic method that is used when the fine needle aspiration biopsy is insufficient. The indication for BG is therefore the need to distinguish specific changes in the thyroid gland, an example of which may be Riedel’s thyroiditis. The doctor may also order a core needle biopsy if there is a possibility of lymphoma.

Thyroid biopsy – contraindications

In the case of some thyroid lesions, biopsy may be omitted due to the low risk of their cancerous nature. This applies, inter alia, to simple cysts without disturbing features, autonomic or spongy nodules, as well as nodules not exceeding 5 mm in diameter. However, it should be remembered that even the smallest nodule qualifies for the BACC test in the case of people at increased risk (e.g. RET mutation, metastasis of thyroid cancer).

The main contraindications for a thyroid biopsy are:

1. the appearance of purulent lesions on the skin of the neck;
2. severe hemorrhagic diathesis in the subject.
3. use of anticoagulants – this is a relative contraindication, and undergoing FNAB surgery depends on the risk of thrombotic complications;
4. cough – may be a temporary contraindication to a biopsy.

Fine needle biopsy of the thyroid gland – preparation and course

Fine-needle biopsy of the thyroid gland does not require any special preparations from patients, however, it should be preceded by thorough diagnostic tests that will confirm the necessity of its performance. Before the biopsy, make sure that there are no contraindications to the procedure, and inform your doctor about the medications you are taking.

Immediately before the examination, remove any ornaments from the hair and neck, and then lie down in the place indicated by the person performing the procedure. Then the skin is disinfected. While taking a snip changes in the thyroid gland the patient should lie still, say nothing and not swallow.

The fine-needle biopsy itself involves puncturing the nodule with a very thin needle (0,4 – 0,6 mm) in order to collect material from it for cytological examination. This operation is performed under ultrasound supervision. It takes a very short time (a few seconds) and, apart from a slight stinging sensation, it is completely painless. The duration of the visit should not exceed 15 minutes. After the examination, it is recommended to press the injection site with the gauze for several or several minutes. After that, you can resume your normal daily activities.

Also read about other thyroid tests:

1. Thyroid profile. What should a thyroid test package include?
2. Thyroid scintigraphy – what does the examination look like?

Thyroid biopsy – possible complications

After the biopsy, a small bruise may remain at the site where the sample was taken. Transient pain, hematoma, swelling, or fainting are extremely rare following a biopsy. Infection can rarely occur, which are primarily atopic dermatitis, diabetes, tuberculosis and HIV patients.

The rarest are serious biopsy complications:

1. a hematoma or hemorrhage that requires surgical intervention;
2. retrograde laryngeal nerve palsy – may develop two days after surgery, symptoms resolve within four months;
3. the implementation of cancer cells along the needle track – applies only to core-needle biopsy.

Thyroid biopsy – prognosis

The prognosis is usually positive if thyroid biopsy confirms the presence of nodules. Only 5-10 percent. cases are malignant tumors. According to current statistics, when malignant nodules are detected, the survival rate for men is 76,8%, and for women it is 90,7%. The sooner a change is detected, the greater the chance of a cure.

Waiting for biopsy results it is usually 2 to 3 weeks. In very rare cases, it may be necessary to repeat the test. Such a necessity may arise when the collected sample does not contain thyroid tissues, and there is not enough fluid and cells of colloidal nodules or thyroid tissues in the sample.

How accurate is a thyroid biopsy?

A section taken from a thyroid nodule during a biopsy is then subjected to a cytological examination. The analysis of the sample does not always give the full picture, because the tests are of limited effectiveness – they do not distinguish between follicular adenoma and follicular carcinoma. The problem also arises in the diagnosis of autoimmune thyroiditis and papillary cancer.

In some cases, the fine needle biopsy does not detect thyroid cancer. The measurement error appears even in 1,3–13,6%. material analyzes from BACC. The reasons for this may be: a non-obvious form of cancer (e.g. cystic), an error during the biopsy or insufficient amount of material analyzed. False positive results of a fine needle biopsy are about 1 percent. cases.

Thyroid biopsy – price

A thyroid biopsy is a diagnostic test that can be performed at many medical analysis laboratories or medical centers. If we receive a referral for the examination, it will be possible to perform it free of charge under the National Health Fund. You can also perform the test for a fee. It depends on the facility what it will be like price of a thyroid biopsy. The cost ranges from PLN 150 to PLN 300.

See also: New methods of safe thyroid surgery