What is multiple endocrine neoplasia type 2 (MEN2)?

Multiple endocrine neoplasia type 2 (MEN2) is a rare condition that can run in families. It causes tumours that usually affect endocrine glands. Endocrine glands make chemicals called hormones to control many functions in the body.

There are two types of MEN. They are MEN1 and MEN2. Although their names are similar, they are separate conditions.

What causes MEN2?

Your body is made up of tiny building blocks called cells. Inside every cell is a set of genes. These genes are the instructions the cell needs to work normally. Sometimes, the structure inside a gene is permanently changed, so the gene no longer gives the correct instructions. This change is called a gene mutation.

People with multiple endocrine neoplasia type 2 (MEN2) are born with a mutation in the RET gene. If you have a mutation in this gene, you are more likely to develop certain types of tumour.

What tumours are caused by MEN2?

Tumours caused by MEN2 can be cancerous (malignant) or non-cancerous (benign). Cancers can spread to other parts of the body, but non-cancerous tumours do not spread. Some tumours make the gland they are growing in produce large amounts of hormones.

The endocrine glands that are most likely to be affected by MEN2 are:

  • the thyroid gland, which is in the front of the neck
  • the adrenal glands, which are on top of the kidneys
  • the parathyroid glands, which are in the front of the neck.

Types of MEN2

There are 3 types of MEN2:

  • MEN2A
  • MEN2B
  • familial medullary thyroid cancer (FMTC).

All 3 cause a higher risk of a type of thyroid cancer called medullary thyroid carcinoma.

People with MEN2A may also develop:

  • tumours of the adrenal gland, for example a phaeochromocytoma
  • overactive and enlarged parathyroid glands.

People with MEN2B may also develop:

  • tumours of the adrenal gland
  • non-cancerous tumours (neuromas) on the lips, tongue and lining of the mouth, and bowel.

How MEN runs in families

Genes are passed from parent to child (inherited) when a sperm and egg join to start a pregnancy (conception).

How genes are passed on

We have more information about how genes are passed on.

We have two copies of each gene – one from our mother and the other from our father:

  • the sperm contains one copy of the father’s genes
  • the egg contains one copy of the mother’s genes.

You only get one copy of each of your parent’s genes. So if one parent has the RET gene mutation, either you will get the copy containing it, or you will not. There is a 1 in 2 (50%) chance the mutation is passed on.

A small number of people are the first in their family to have the RET gene mutation. This means your parents did not have it. But any children you have will have a 1 in 2 (50%) chance of inheriting it from you.

Diagnosing MEN2

You will be diagnosed with MEN2 if:

  • you have one or more tumours commonly linked to MEN2 and the RET gene mutation
  • you have one tumour linked to MEN2, and a member of your family has MEN2
  • a genetic test shows you have the RET gene mutation.

If you have a tumour that could be caused by MEN2, your doctors will arrange tests to check for other tumours. They will also ask you about any illnesses your close relatives have had. This is to check whether other family members may have had MEN2 tumours.

Genetic testing

If your doctor thinks you may have MEN2, you will usually be offered genetic testing. A sample of blood is taken to check for the RET gene mutation.

Your specialist doctor will explain:

  • what your genetic test result shows
  • how this may affect your health
  • how this may affect other people in your family.

Screening and tests for MEN2 tumours

The tests below can be used to find the cause for particular symptoms. They can also be used to check for MEN2 tumours before they cause any symptoms. This is called monitoring or screening. Screening helps your doctor find and treat tumours at an early stage, often before symptoms begin to cause problems.

Problems caused by MEN2 can often be found at an early stage and successfully treated or controlled. The earlier someone knows they have MEN2, the sooner they can have treatment and monitoring to help prevent problems.

You usually have these tests done at the hospital and go home on the same day (outpatient appointment).

  • Blood tests

    Blood tests are used to check the levels of different hormones and chemicals in your body.

  • 24-hour urine collection

    This test may be done to check for adrenal gland tumours. It measures the level of hormones called catecholamines. People with adrenal gland tumours often produce too much of these hormones.

  • Biopsy

    A biopsy is when a doctor takes a sample of cells or tissue from a part of the body. The sample is then examined under a microscope to look for changes in the cells.

  • Ultrasound scan

    An ultrasound scan uses sound waves to build up a picture of the organs inside the body.

  • CT scan

    A CT scan takes a series of x-rays that build up a 3D picture of the inside of the body.

  • MRI scan

    An MRI scan uses magnetism to build up detailed pictures of your body. 

  • MIBG scan

    People who may have adrenal gland tumours may be offered this test. It involves having an injection of I-123-MIBG. This is mildly radioactive iodine, which is absorbed by adrenal cells. The body is then scanned to check for areas that have absorbed the iodine.

    The dose of radiation from the scan is very low. It is about the same amount you get from an x-ray. Almost all the radiation leaves your body within a week. If you are planning to travel abroad within 3 months of the scan, let the doctor in the scanning department know. They can give you a letter to show to customs officials. This is because ports and airports have very sensitive radiation detectors that may pick up tiny amounts of radioactivity.

Treating MEN2 tumours

A team of specialists will plan your treatment and care. This may include:

  • an endocrinologist – a doctor who treats problems with the endocrine system
  • an endocrine surgeon – a surgeon who operates on endocrine glands
  • an oncologist – a cancer doctor
  • a clinical geneticist – a doctor with specialist experience in genetics
  • a radiologist – a doctor who looks at different types of scans
  • a pathologist – a doctor who looks at changes in the cells of tumours
  • a specialist endocrine nurse – a nurse who can give you support and information about living with MEN2.

Your treatment will depend on the type of tumour and where it is. You may need surgery to remove tumours and drugs to control symptoms.

During and after treatment, you will be monitored regularly with tests and scans. This helps your team to adjust your treatment as needed, and to check for any new problems.

Your doctors may ask you to take part in a clinical trial to find out more about MEN2 and to look at new treatments. They will talk to you about the trial, so you fully understand what it involves. You can choose not to take part or leave the trial at any stage. You will still get the standard treatment available.

Medullary thyroid carcinoma (MTC)

MTC is a cancer of the thyroid gland. It is the most common tumour caused by MEN2. Most people with MEN2 will develop MTC unless they have an operation at an early age. This operation involves removing the thyroid gland before the cancer starts to grow.

The thyroid is a small gland in the front of the neck, just below the voicebox (larynx). It is made up of two parts (lobes). The thyroid produces two hormones. These are thyroxine (T4) and triiodothyronine (T3). These hormones keep the body functioning at its normal rate. The part of the thyroid where MTC can develop also makes a hormone called calcitonin.

The thyroid


Signs and symptoms of MTC

The signs and symptoms of MTC include:

  • a painless lump in the neck
  • changes in breathing or swallowing due to the tumour pressing on the windpipe (trachea) or gullet (oesophagus)
  • feeling hot and the skin turning red (flushed)
  • loose poo (stools) or diarrhoea.

Diagnosing MTC

You will have a scan of your neck to check the thyroid gland and the lymph nodes. Lymph nodes drain fluid from the tissues and help the body fight infections. There are groups of pea-sized lymph nodes on both sides of the neck (see the illustration above). If cancer spreads from the thyroid, the first place it usually spreads to is nearby lymph nodes.

The doctor will arrange to take a biopsy from any abnormal areas that show up on the scan. The doctor puts a needle into the area and withdraws some cells into a syringe. This is called a fine needle aspiration cytology (FNAC).

You will have a blood test to check the level of the hormone calcitonin in your blood. You will also usually have a 24-hour urine test.

Treating MTC

The main treatment for MTC is surgery to remove the thyroid gland (thyroidectomy) and nearby lymph nodes.

If MTC is causing symptoms but has spread beyond the thyroid gland, sometimes it cannot be removed by surgery. Instead, it may be treated with radiotherapy. Radiotherapy uses radiation to destroy cells.

MTC may also be treated with the targeted drug treatments vandetanib or cabozantinib. Targeted drug treatments work by blocking signals in the thyroid cancer cells that make them grow and divide. These treatments cannot cure MTC, but they may help control it.

Preventing MTC

Almost everyone with MEN2 will develop MTC. Because of this, children and young adults with the RET gene mutation usually have surgery to remove the thyroid gland to prevent cancer developing. The earlier this is done, the more likely it is to prevent MTC. In children with MEN2A, surgery is often done before they are 5 years old. Babies with MEN2B may have surgery before they are 1 year old.

Follow-up for MTC

After the thyroid gland is removed, you will need to take thyroid hormone tablets (levothyroxine) every day for the rest of your life. These replace the thyroid hormones your body needs to function. You will have regular blood tests to check your thyroid hormones are at the right level.

You will also have blood tests to check the levels of calcitonin and a protein called CEA. These blood tests are used to look for any signs of the MTC coming back after surgery.


The adrenal glands are on top of the kidneys. Phaeochromocytoma is a tumour of the adrenal gland. It is usually non-cancerous.

Position of the kidneys, bladder and adrenal glands

People with MEN2A or MEN2B can develop phaeochromocytoma. One or both of the adrenal glands can be affected. Phaeochromocytoma can cause the adrenal gland to make large amounts of hormones called catecholamines. One of these hormones is adrenaline (epinephrine). Adrenaline regulates the heart rate and blood pressure. Having too much adrenaline can cause symptoms such as:

  • severe headaches
  • a fast heart rate (palpitations)
  • excessive sweating
  • feeling anxious
  • increased appetite
  • feeling sick
  • trembling hands
  • pain in the chest or tummy area (abdomen).

Diagnosing phaeochromocytoma

Tests used to investigate and diagnose phaeochromcytoma include:

  • a blood test or 24-hour urine test, to check the levels of catecholamines in the body
  • a CT or MRI scan of the tummy area (abdomen), to check the kidneys and adrenal glands
  • an MIBG scan, although this is less common than a CT or MRI scan.

Treating phaeochromocytoma

The main treatment for phaeochromocytoma is an operation to remove the affected adrenal gland. If you are diagnosed with phaeochromocytoma, you will start taking a drug called an alpha blocker. This stops problems in your body caused by too much adrenaline. Before your operation, you will take a higher dose of the drug. This causes temporary side effects, including a stuffy feeling in the nose and dizziness when standing. You will be encouraged to drink plenty of fluids during this time.

The operation is usually done using keyhole (laparoscopic) surgery. The surgeon uses a tube with a camera on the end (laparoscope) and special surgical tools. They operate through 3 to 4 small cuts (incisions) made in the side of the tummy (abdomen) or back. Operations to remove larger tumours may be done through one larger incision in the tummy.

If just one adrenal gland is removed, the other gland will soon take over the work of two adrenal glands. It will make the hormones your body needs. You will have blood or urine tests every year to check the adrenal gland is healthy.

If both adrenal glands are removed, you will need to take hormone replacement tablets every day for the rest of your life.

Overactive parathyroid glands

The parathyroid glands are just behind, or sometimes in, the thyroid gland. This is in the front of the neck.

If you have MEN2A, the parathyroid glands may become large and overactive. This is most likely to happen when you are 20 to 40 years old.

The thyroid and parathyroid glands

Parathyroid glands make a hormone called parathyroid hormone (PTH). PTH helps control calcium levels in the body. People with overactive parathyroid glands may make too much PTH. This can cause high levels of calcium in the blood. This is called hypercalcaemia.

High levels of calcium in the blood can make you:

  • sick (nauseous)
  • thirsty
  • drowsy
  • confused
  • unwell
  • constipated
  • need to pee (pass urine) often.

Most of the calcium in your body is stored in your bones. One way PTH raises calcium levels in the blood is by making the bones release calcium. This means if hypercalcaemia is left untreated, eventually the bones get thinner due to loss of calcium. This is called osteoporosis. It can cause bone pain and make bones break easily.

The kidneys can also be affected by high calcium levels in the blood. Some people develop kidney stones, or their kidneys may become damaged. Most people are treated early, so this is not usually a problem.

As part of your screening tests, you will have a blood test every year to check your calcium and PTH levels. But it is still important to tell your doctor if you have any symptoms that may be caused by high levels of calcium in between screening tests.

Treating overactive parathyroid glands

The main treatment for overactive parathyroid glands is an operation to remove the affected glands.

If the surgeon needs to remove all of your parathyroid glands, you will need to take tablets for the rest of your life to keep your calcium levels in balance.

If the surgeon leaves some of the parathyroid glands, sometimes the remaining glands can become overactive after surgery. If this happens, you may need another operation to remove the affected parathyroid glands.

Your surgeon will explain the different treatments for overactive parathyroid glands so you can decide together what is right for you.

Your doctor may give you drugs called calcimimetic agents to reduce symptoms of overactive parathyroid tissue. They reduce the amount of parathyroid hormone made by the glands.


Neuromas are non-cancerous growths that may develop on the eyelids and lips, and on the lining of the mouth and bowel in people with MEN2B. Neuromas are painless and do not usually need treatment. They often look like little bumps and may be pale or the same colour as surrounding tissue. They can make the lips look larger and fuller. Neuromas in the bowel can cause constipation or diarrhoea. Your doctor or specialist nurse can give you information and advice about managing this.

Planning a family

If you have MEN, there is a 1 in 2 (50%) chance that any child you have could inherit it from you. You may have questions about this if you are planning to get pregnant or start a pregnancy. Your genetics specialist can talk to you about this if you have questions.

We have more information about planning a family and inherited cancer risk.

Your feelings

Multiple endocrine neoplasia can be difficult to cope with. There is the uncertainty of whether you will develop tumours or what new symptoms mean. You may have to make decisions about treatment. It is important to talk to your MEN specialist, GP or nurse. They will be happy to answer any questions you have.

There is no right or wrong way to cope, but help is there if you need it. If you are struggling, talking about your feelings and worries may help. You may want to talk to a partner, family member or friend. You can also talk to our cancer support specialists on 0808 808 00 00. Or you can share your thoughts with members of our Online Community.

You may also find it helpful to contact AMEND (the Association for Multiple Endocrine Neoplasia Disorders) for more information and support.