What is Multiple Endocrine Neoplasia Type 1 (MEN1)

Multiple endocrine neoplasia type 1 is a rare condition that affects the endocrine system. The endocrine system is a network of glands in the body that release hormones, which are like chemical messengers that tell your cells what to do for growth, reproduction, and using energy.

MEN1 can cause tumors to form in endocrine glands. Tumors in these glands may release extra hormones that can cause symptoms and lead to certain conditions. The glands that are affected most commonly are the pituitary gland, pancreas, and small glands near the thyroid gland (parathyroid glands).

MEN1 tumors are usually noncancerous (are benign), but some tumors may form cancer.

MEN1 can cause neuroendocrine tumors, also called islet cell tumors. These tumors can become cancerous (malignant).

MEN1 can also cause carcinoid tumors that develop in the lungs, the thymus gland, and the gastrointestinal tract.

What are the causes?

This condition is caused by an inherited abnormal change (mutation) in a gene.

What increases the risk?

You are more likely to develop this condition if:

• You have a family history of MEN1 or MEN2 (multiple endocrine neoplasia type 2).

What are the signs or symptoms?

Symptoms of this condition include:

• An overactive parathyroid gland (hyperparathyroidism),which may cause:
  • Tiredness.
  • Kidney stones.
  • Weak bones.
  • Nausea and vomiting.
  • Constipation.
  • Indigestion.
• An overactive pituitary gland, which may cause:
  • Headache.
  • Vision changes.
  • Infertility.
  • High blood pressure.
  • Excess growth of certain areas of the body (acromegaly) or excess growth in children (gigantism).
  • Excess production of cortisol (Cushing disease).
• An overactive pancreas gland, which may cause:
  • High blood sugar (hyperglycemia). This may cause increased thirst and frequent urination.
  • Low blood sugar (hypoglycemia). This may cause confusion, sweating, and a fast heartbeat.
  • Diarrhea.
  • Skin rash.

How is this diagnosed?

This condition may be diagnosed based on your medical history and a physical exam. A genetic test may be done to check for the gene mutation. Sometimes the condition is discovered when a tumor is found in your body, or if your health care provider finds out that you produce too many hormones.

You may also have other tests, including:

• Urine tests.
• Blood tests.
• MRI.
• CT scan.
• PET scan.
• Nuclear medicine scans.
• Endoscopy.
• Ultrasound.

How is this treated?

This condition may be treated with:

• Medicine.
• Surgery.
• Radiofrequency ablation, which uses radio waves to destroy cancer cells.
• Chemotherapy.

Treatment will depend on the location of the tumor and whether it is causing symptoms.

Follow these instructions at home:

• Return to your normal activities as told by your health care provider. Ask your health care provider what activities are safe for you.
• Do not use any products that contain nicotine or tobacco, such as cigarettes and e-cigarettes. If you need help quitting, ask your health care provider.
• Maintain a healthy diet that includes lots of fruits and vegetables, low-fat dairy products, lean meats, and fiber.
• Drink enough fluid to keep your urine clear or pale yellow.
• Keep all follow-up visits as told by your health care provider. This is important.
• Ask to meet with a genetic counselor to discuss the results of your genetic testing and to understand what it means for your family.

Contact a health care provider if:

• You feel sad or depressed.
• You are bruising easily.
• You have constipation or diarrhea that is not managed with medicines.
• You are dehydrated or you feel weak.
• You feel confused.
• You have pain in your abdomen that does not go away.

Get help right away if:

• You have a seizure.
• You develop symptoms of high or low blood sugar (glucose).
• You are unable to eat and drink without vomiting.
• You break a bone.
• You develop any symptoms that cannot be controlled.

Summary

• Multiple endocrine neoplasia type 1 (MEN1) is a rare condition that affects the endocrine system.
• This condition can cause tumors to form in endocrine glands, such as the pituitary gland, pancreas, and small glands near the thyroid gland (parathyroid glands).
• This condition may be diagnosed based on your medical history, a physical exam, and other tests. A genetic test may be done to check for an abnormal change (mutation) in a gene, which is what causes this condition.
• Treatment will depend on the location of the tumor and whether it is causing symptoms.
• Ask to meet with a genetic counselor to discuss the results of your genetic testing and to understand what it means for your family.