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Medullary Thyroid Carcinoma

Medically reviewed by Last updated on Jan 5, 2022.

What is medullary thyroid carcinoma?

  • Medullary thyroid carcinoma is also called MTC. It is a kind of tumor (abnormal growth) found in your thyroid gland. The thyroid gland is a small, butterfly-shaped organ in the front area of your neck. The tumor comes from a part of the thyroid gland called parafollicular cells, or C-cells. These cells make the hormone (special body chemical) calcitonin that controls the amount of calcium in your blood. You may be able to feel the tumor with your fingers and it may grow. The tumor may also be painless and you may not know it is there.
  • Normal cells in your body split and make more cells when needed. When cells grow and split without control or order, they often make too much tissue (tumor). These abnormal cells may grow in nearby healthy organs or tissue. They may also break away from the tumor, and spread to other parts of your body. Cancer that spreads is called metastasis, and it is harder to control. The chances of surviving MTC are better if it is found and treated early.

What causes medullary thyroid carcinoma?

MTC is most often caused by changes in your genes. Genes are little pieces of information that tell your body what to do or make. You may have been born with the genes that cause MTC. Having a close family member who has had MTC increases your risk for having this condition. Your cause of MTC may be unknown. The following may increase your risk of having MTC:

  • Thyroid disease: Having too much thyroid hormone or an autoimmune thyroid problem (your body attacks your thyroid).
  • Previous radiation therapy: Head or neck radiation therapy, earlier in life, increases your risk of having MTC.

What are the types of medullary thyroid carcinoma?

  • Sporadic: This is the most common type of MTC. This kind of MTC is not passed on by a family member, and the cause may be unknown. Women 40 years old and older may be at higher risk for this type of MTC.
  • Hereditary: These types of MTC may be passed on from parent to child. Your parents may pass on a mutated (changed) gene that increases your risk of having MTC.
    • Familial: This is more commonly found in adults 40 to 50 years of age. There are usually no other tumors or diseases linked to this type of MTC.
    • Multiple endocrine neoplasias: This is a condition when tumors are also found in other organs of your body that make hormones. These include your adrenal and parathyroid glands. Other disorders such as Hirschsprung disease and skin amyloidosis may come with this condition. Ask your caregiver for more information about these medical conditions.

What are the signs and symptoms of medullary thyroid carcinoma?

You may have no signs or symptoms of MTC at first. Over time, you may have one or more lumps (nodules or goiters) in your neck. You may also have any of the following:

  • Bone pain.
  • Flushed (red) skin.
  • Hoarse (rough) voice.
  • Increased fat on your neck, collar area, and back with puffiness of your face.
  • Trouble swallowing.
  • Diarrhea (loose, watery bowel movements).
  • Shortness of breath or noisy breathing, especially when breathing in.

How is medullary thyroid carcinoma diagnosed?

Your caregiver will ask you about your health history. This includes information on what signs and symptoms you have, and when they started. You may also be asked about your family's health. Your caregiver will look and feel for lumps or other signs of problems on your neck. You may also need any of the following tests:

  • 24 hour urine test: During this test you will need to collect all of your urine for 24 hours. You will urinate into a container and the urine will be put into a jug. The jug will need to be kept cold. If you urinate during the night, you will need to save that urine. Caregivers will measure and record how much you urinate. At the end of 24 hours, the urine will be sent to a lab for tests.
  • Blood tests: You may need blood taken to give caregivers information about how your body is working. The blood may be taken from your hand, arm, or IV.
  • Fine-needle biopsy: This is a procedure where a very small piece of your thyroid gland is taken for tests. Your caregiver may use medicine to numb the front part of your neck. A small needle is used to get the tissue sample from your thyroid gland. After the sample is collected, a bandage may cover the biopsy area. The sample is sent to the lab for tests.
  • Genetic screening: This may be done to confirm if you or other family members have MTC. This will also give your caregiver more information on how to treat your condition.
  • Imaging tests: Certain tests use a special dye to help pictures show up better. People who are allergic to iodine or shellfish (lobster, crab, or shrimp) may be allergic to some dyes. Tell your caregiver if you are allergic to shellfish, or have other allergies or medical conditions.
    • Computed tomography scan: This is also called a CT scan. A special x-ray machine uses a computer to take pictures of your neck and chest. It may be used to look at your tissues, bones, muscles, and blood vessels. Before taking the pictures, you may be given dye through an IV in your vein.
    • MRI: This test is also called magnetic resonance imaging. During the MRI, pictures of your thyroid gland are taken. An MRI may also be used to look at the organs, muscles, joints, bones, or blood vessels. You will need to lie still during the test. Never enter the MRI room with an oxygen tank, watch, or any other metal objects. This can cause serious injury.
    • Positron emission tomography scan: This test is also called a PET scan. A PET scan shows how much blood and oxygen is flowing to your neck area. It may also show other parts of the body with cancer.
    • Thyroid scan: This test shows caregivers how well your thyroid is working. Radioactive dye is put into your IV or is given to you to drink. The working part of the thyroid gland absorbs (soaks up) the dye. Two to 48 hours later, caregivers put a machine called a scintillator over your neck. The machine takes pictures showing the areas of your thyroid that absorbed the dye.
    • Ultrasound: This is a test using sound waves to look inside your neck. Pictures of your thyroid gland show up on a TV-like screen.

How is medullary thyroid carcinoma treated?

  • Surgery: You will need surgery to remove your thyroid gland. With this surgery, lymph nodes (bean shaped tissue that can trap cancer) may also be removed. Ask your caregiver for more information about this surgery.
  • Other possible treatments: The following treatments may be used after you have surgery to remove your thyroid gland:
    • Chemotherapy:
      • This medicine, often called chemo, is used to treat cancer. It works by killing tumor cells. Chemotherapy may also be used to shrink lymph nodes that have cancer in them. Once the tumor is smaller, you may need surgery to cut out the rest of the cancer.
      • Many different chemotherapy medicines are used to treat cancer. You may need blood tests often. These blood tests show how your body is doing and how much chemotherapy is needed. Chemotherapy can have many side effects. Caregivers will watch you closely and will work with you to decrease side effects. Chemotherapy can cure some cancers. Even if the chemotherapy does not cure your cancer, it may help you feel better or live longer.
    • Radiation therapy: This may include external beam radiation therapy. Radiation therapy uses x-rays or gamma rays to control bleeding, and shrink the tumor. It keeps cancer cells from splitting into new cells, which is one way cancer spreads. Lymph nodes with cancer are also treated with radiation. It may be given after surgery to kill the cancer cells that were not removed. This treatment may be given along with chemotherapy. Ask your caregiver for more information about external beam radiation therapy.

When should I call my caregiver?

Call your caregiver if:

  • You have nausea (upset stomach) or vomiting (throwing up).
  • You have trouble swallowing.
  • You notice new lumps on your neck.
  • Your voice becomes hoarse.
  • You have questions or concerns about your condition, treatment, or care.

When should I seek immediate help?

Seek care immediately or call 911 if:

  • You suddenly have trouble breathing.
  • Your symptoms get worse or do not go away even after taking medicine.

Where can I get support and more information?

Having a medullary thyroid carcinoma may be a life-changing condition for you and your family. You and those close to you may feel scared, angry, or sad. These feelings are normal. Talk to your caregivers, family, or friends about your feelings. You may also want to join a support group with other people who have MTC. Contact any of the following:

  • American Cancer Society
    250 Williams Street
    Atlanta , GA 30303
    Phone: 1- 800 - 227-2345
    Web Address:
  • American Thyroid Association
    6066 Leesburg Pike, Suite 550
    Falls Church , VA 22041
    Phone: 1- 703 - 998-8890
    Phone: 1- 800 - 849-7643
    Web Address:
  • National Cancer Institute
    6116 Executive Boulevard, Suite 300
    Bethesda , MD 20892-8322
    Phone: 1- 800 - 422-6237
    Web Address:

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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