What is Multiple Endocrine Neoplasia Syndrome and What Causes It?

multiple endocrine neoplasia

What is Multiple Endocrine Neoplasia Syndrome and What Causes It?

The MEN syndromes or multiple endocrine neoplasia syndromes are a group of disorders affecting the endocrine glands!

Endocrine glands are the hormone-controlling system in our body.

These hormones are vital for our body as they are chemical messengers guarding the functions of cells and tissues.

In essence, the Multiple Endocrine Neoplasia affects the secretion of such hormones as it involves tumors of at least two such glands.

Major glands affected by the disorder include:

  • Pituitary
  • Thyroid
  • Parathyroid
  • Adrenal Pancreas

These tumors can either be cancerous (the malignant one) or non-cancerous (the benign one).

However, cancerous tumors are more severe and are often fatal!

Moreover, there are different types of multiple endocrine neoplasia syndromes:

  • MEN Type 1
  • Type 2 – This is further of two types – MEN 2a and MEN 2b
  • Type 4

We will learn more about these types in the following sections!


Multiple Endocrine Neoplasia (MEN) 

The syndrome is classified based on the type of tumor causing the condition.

The various types of MEN are:

#1. Multiple Endocrine Neoplasia Type 1

This MEN type is also known as the multiple endocrine adenomatoses or Wermer’s syndrome.

Its frequency is one patient per 30,000 people. So, you can see it’s rare.

Regardless, the disease can affect all age groups, races, and genders and is mainly caused by a genetic mutation.

Usually, children of a MEN patient have a 50% chance of getting the same disease.

This type is characterized by the tumor affecting various glands of the endocrine system and not just one gland.

On the off chance, if you are suffering from a tumor in one gland, you are actually not suffering from MEN type 1.

Although the tumors found here are benign, it definitely causes problems in hormone secretion.

However, half of the people suffering from MEN1 still have the chance of developing cancer.

It usually affects the following glands of the endocrine system:

#1. Parathyroid

Almost all the people suffering from Type 1 disorder have impaired parathyroid glands. 

They are often the first glands to get affected in the medical condition.

The tumor usually stimulates the gland to over secrete the parathyroid hormone.

This further leads to hypercalcemia (high calcium level in your blood) as the hormone promotes calcium levels in the blood.

#2. Pituitary Gland

This disease is often characterized by benign tumors in the anterior pituitary. 

Major effects of such tumors are observed because of their pressure on other nearby glands.

Hence, it usually gives out signs like headaches.

The pituitary secretes many stimulatory hormones and, thus, its impairment can lead to impaired body functions.

#3. Pancreas

These tumors can also affect the islet cells of the pancreas and the inner lining of the duodenum.

This, in turn, can promote abnormal secretions of many hormones.

However, the major difference between the tumors formed in other glands and here is that they can be either malignant or benign.

Though, malignancy is usually rare.

Usually, people suffering from MEN Type 1 face gastrinomas which can further cause many disorders.

#4. Adrenal Gland

These are actually the most benign tumors.

However, there are other types of tumors formed in Type 1 too like:

  • Lipomas – benign fatty tumors under the skin
  • Carcinoid tumors


#2. Multiple Endocrine Neoplasia Type 2

The MEN 2 is usually caused by the mutations in the RET gene and are of two types:

#1. Multiple Endocrine Neoplasia Type 2a

People suffering from this disorder usually develop tumors in any two or three of the following glands:

  • Thyroid
  • Adrenal
  • Parathyroid

Sometimes they also face skin issues like itchy skin called cutaneous lichen amyloidosis.

Apart from this, almost 50% of the people suffering from type 2 have the potential risk of medullary thyroid cancer.

40 to 50% of people suffer from tumors of the adrenal gland causing high blood pressure and many more issues.

Some of them could also have over-functioning parathyroid.

The next type is MEN TYPE 2b, which again affects specific glands of the system.

#2. Multiple Endocrine Neoplasia Type 2b

This disorder is usually a combination of:

  • Medullary thyroids
  • Pheochromocytomas
  • Growth around nerves 

What surprising is the fact that usually people with no medical history of such a disorder are found suffering from it?

This is because it is mainly caused by mutation.

The medullary thyroid cancers in the patients of Type 2B appear at a young age and are often spotted in 3 months old kiddos.

This type of tumor spreads faster than those occurring in Type 2A, in fact.

Apart from this, people have also reported neuromas in mucous membranes occurring around lips and mouth.

They might also occur around the eyes, even in the conjunctiva.

If we compare the two types of Multiple endocrine neoplasias, we can clearly see the difference between men1 and men2 lies in malignancy!

Type 1 has rare chances of malignant tumors developing as compared to the malignancy of tumors in type 2.

Other than these two types, another type of MEN exists, which is quite rare.


#3. Multiple Endocrine Neoplasia Type 4

This type of neoplasia shows similar signs and symptoms as Type 1. 

Though, its causative agent is a mutation in a different gene.

The tumors developed in this type usually affect:

  • Parathyroid
  • Pituitary

It can even have an impact on other endocrine glands and organs.

After looking at the severity of the various types of neoplasia, one must be aware of what symptoms they show!

The symptoms help a person seek the right multiple endocrine neoplasia prognosis and treatment.

In line with this, the next section helps you identify the symptoms of the disease.


Multiple Endocrine Neoplasia Symptoms

The symptoms of the disease usually vary from person to person.

Some of the patients can suffer from all the symptoms while others could spot just one or two.

The various MEN symptoms that you must look out for before visiting your doc for MEN syndrome are:

#1. Multiple Endocrine Neoplasia Type 1 Symptoms

Some of the common symptoms observed in patients diagnosed with MEN 1 are:

  • Weakness, Tiredness, and Muscular Pain 

This happens due to hypersecretion of the parathyroid hormone. 

This can even cause thinning of bones, constipation, and stones in the kidney.

  • Abdominal Pain 

This is the result of an increase in the levels of gastrin, ulcers, and inflammation in the esophagus and stomach. 

  • Changes in vision and headaches 
  • Abnormal sexual functions and fertility
  • Abnormal stature and scaly skin 

This is a condition called Acromegaly where the bones enlarge and stature becomes abnormal. 

Usually, the skin also shows scaliness, and layers of the scalp fold up. The face protrudes forward.

  • Mental disability

Cushing’s syndrome – the most common signs of this disorder include tiredness, fatigue, and loss of emotional control.

  • Over lactation

This is essentially the overproduction of breast milk.

#2. Multiple Endocrine Neoplasia Type 2 Symptoms

The various symptoms of type 2 MEN include:

  • Neuromas 

They are small blisters or bumps around the nerves of the mucous membrane. In Type 2, they usually grow around the lips and glistening areas of the eyes, like conjunctiva.

  • Eyelids and lips thicken out because of the various growths.
  • Abnormal bones and thighs as usually the parathyroid hormone secretion becomes abnormal. Bone and joint pain is also observed.
  • Loose joints and excess lengthening of the bones.
  •  The curvature of the spine.
  • The patients look tall and slender because of the excessive growth of the bones.
  • Small benign tumors appear on the tongue and the eyelids.
  • The large intestine enlarges causing severe digestion abnormalities like diarrhea.

Looking at the various symptoms, most of you would want to prevent it from ever happening at all.

And for that, one needs to eradicate the root cause of the disease.

However, it’s unfortunate that there is no way of preventing it!

Wondering why?

Read about the causes below to understand the reasons!


Causes of Multiple Endocrine Neoplasia

The group of disorders called Multiple Endocrine Neoplasia is mainly caused by mutations in the genes.

These mutations usually occur in:

  • MEN1 gene
  • RET gene
  • CDKN1B gene

The mutations in these genes yield specific types of neoplasia.

Here are the main risk factors of Multiple Endocrine Neoplasia syndromes.

#1. Causes of MEN TYPE 1

Type 1 neoplasia is caused by a mutation in the MEN1 gene

This gene is mainly responsible for producing the protein menin

It works as a tumor suppressor keeping out the cells from dividing abnormally.

When the mutation occurs, it inactivates the gene and we no longer have the menin protein to control the cell’s growth.

This further causes the Type 1 MEN.

#2. Causes of MEN TYPE 2

Mutations in the RET gene are responsible for this type of neoplasia. 

The gene usually promotes the production of the protein responsible for cell signaling.

This protein stimulates chemical reactions that make a cell respond to the external environment.

Moreover, the mutation stimulates the overproduction of the protein causing more cell division and growth causing tumors.

#3. Causes of MEN TYPE 4

The mutation in the CDKN1B gene causes the type 4 disorder. 

This gene is responsible for producing a protein that acts as a tumor suppressor.

Mutations again inactivate it and, thus, lead to over division of the cells.

With this out of the way, you must also have some basic idea about the symptoms and the causes to supplement your research.

Now, many of you might ask, how do you test for multiple endocrine neoplasia?

Well, yes, the symptoms are not just enough to confirm the disease. Many other conditions can harbor similar signs and symptoms. 

Thus, it’s always better to be sure and not self-diagnose yourself based on an article on the internet.

Hence, if you suspect something is out of the line, you will need a correct diagnosis that involves the following procedures.


Multiple Endocrine Neoplasia Diagnosis

When you visit the doctor with the symptoms of this disorder, the first thing that he will do is ask you about your medical history.

Next will be your physical examination for ruling out the possibilities of any other disorder.

The last step will be tests and exams for the diagnosis of multiple endocrine neoplasia.

These tests and exams usually include:

  • Genetic tests
  • Test for hormone levels in blood and urine
  • Imaging tests (rare)

The tests will help the doctor identify the genetic abnormality in each of the multiple endocrine neoplasia syndromes.

These genetic tests are usually performed in cases where one of your family members has had a history of the disorder.

Whereas, blood tests and urine tests are effective at detecting any abnormal hormonal levels.

Imaging tests which involve tests like ultrasonography, CT scans, MRI, and PET help determine the doctors the location of tumors.

When these tests show positive signs of the disease, the next step that your doctor does is suggesting treatments!

You can read ahead to get a brief idea of the treatments available for the same.


Multiple Endocrine Neoplasia Treatment

Till now, no particular cure has been identified for treating the syndrome at once.

However, doctors treat each gland individually to treat the disorder through the following methods:

#1. Tumour Removal

If the tumor can be removed, docs use surgical methods to remove it. 

For example, small tumors are first watched over to monitor how they grow. If the tumors increase to cause problems, they are treated.

Usually, before removing the tumor, doctors prescribe medicines to balance the abnormal hormone levels.

#2. Removing the Thyroid Gland

Medullary thyroid tumors are usually fatal and must be removed. 

Hence, whenever there’s a diagnosis of type 2A or 2B, doctors suggest removing the thyroid gland.

This measure is implemented even if there is no sign of a medullary thyroid tumor.

However, once the thyroid is removed, people must take thyroid for the rest of their lives.

#3. Drugs

In case thyroid cancer spreads, treatments like drugs and chemotherapy are useful to boost the life expectancy of people.

#4. Hormonal Therapies

Often, hormonal therapies work for people who face hormone deficiency because of the glands’ removal.


The Final Stance

Multiple Endocrine Neoplasia is of various types ranging from benign tumors to malignant ones.

Pituitary and parathyroid tumors are usually benign and not cause much trouble.

However, some of the pancreatic tumors become malignant and might even spread to the liver.

These pancreatic tumors usually occur in TYPE 2.

Hence, between the MEN2 and MEN1 life expectancy, the latter has a higher life expectancy.

Although there is no specific treatment for the syndrome, symptoms respond well to the appropriate methods used.

These syndromes are quite complicated as the tumors often come back. Thus, regular checkups are a must.



Get the answers to some of the commonly asked queries to enhance your understanding of the disorder.

#1. How common is Multiple Endocrine Neoplasia?

Multiple endocrine neoplasia type 1 affects about 1 in 30,000 people while type 2 affects 1 person out of 35,000 people. 

Since type 2 is further of two types, the frequency of type 2A is higher as compared to type 2B!

#2. What is the difference between MEN1 and MEN2?

Mutation in tumor suppressor genes is responsible for MEN1 while a mutation in cell signaling genes is the causing factor in the case of MEN2.

Hence, MEN1 is mostly benign tumors around the neuroendocrine tissues while MEN2 is present as malignant tumors in the form of medullary thyroid tumors, which are often fatal.

#3. What is the most common cause of multiple endocrine neoplasias?

The main cause of Multiple endocrine neoplasias is mutations in various types of genes.

These mutations lead to overgrowth of the cells causing different forms of the tumor to grow around the endocrine glands.

#4. Is multiple endocrine neoplasia fatal?

There are two types of the disorder, Type 1 and Type2.

While the first type shows benign tumors and is hence not fatal. But the second type is associated with fatal tumors like the thyroid tumor. 

Moreover, there is no such cure that can work on all the glands affected by this disease at the same time. 

Doctors treat each gland individually.

#5. Is multiple endocrine neoplasia cancer?

The group of syndromes involves the formation of two types of tumors, one is benign or non-cancerous while the other one is a malignant tumor or the cancerous one. 

Hence, the syndrome is in a way cancer if your body suffers from cancerous growth of tumors.

#6. Is multiple endocrine neoplasia hereditary?

Yes, it is hereditary. 

In fact, children who have a family medical history of the disorder have 50% chances of inheriting it.

Well, with this, I wrap up the blog. Leave your comments down below if you want to ask a question or leave a suggestion. 

Marcus Elburn

Dr. Marcus Elburn is an MSc graduate in Therapeutics, Drug Development, and Human Toxicology. Apart from internal medicine and geriatrics, his areas of research interests include integrative medicine, cardiometabolic risk management, endocrinology and metabolism, and pharmacology of sexual function and dysfunction. Read More... About Me

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