Multiple endocrine neoplasia, type 1 (MEN 1), sometimes called Wermer's syndrome, is a rare disorder that causes tumors in the endocrine glands and parts of the small intestine and stomach. In MEN 1, the endocrine glands — usually the parathyroids, pancreas and pituitary — grow tumors and release excessive amounts of hormones that can lead to disease. However, the tumors are usually not cancerous (benign).

The excess hormones can cause symptoms such as tiredness, bone pain, fractures and kidney stones, as well as stomach or intestinal ulcers. Although MEN 1 can't be cured, if regular testing detects problems, doctors can provide treatment as needed.

MEN 1 is an inherited disorder, meaning people who have the gene mutation can pass it on to their children. Each child has a 50 percent chance of inheriting the disorder.

  • Experience and expertise. Although MEN 1 is rare, you can rely on the expertise and experience of Mayo Clinic specialists to diagnose and provide the best treatment for this complicated disorder. Specialists at Mayo provide the latest interventions for both primary tumors and those that have spread (metastasized).
  • Team approach. Mayo Clinic specialists work as a team to listen, counsel and treat people who have MEN 1. Depending on your specific needs and related conditions, the team may include experts in endocrinology, endocrine surgery, gastroenterology, neurosurgery, oncology, interventional radiology, radiation oncology, chest (thoracic) surgery, liver (hepatobiliary) surgery, medical genetics, and other areas if needed.

At Mayo Clinic, we assemble a team of specialists who take the time to listen and thoroughly understand your health issues and concerns. We tailor the care you receive to your personal health care needs. You can trust our specialists to collaborate and offer you the best possible outcomes, safety and service.

Mayo Clinic is a not-for-profit medical institution that reinvests all earnings into improving medical practice, research and education. We're constantly involved in innovation and medical research, finding solutions to improve your care and quality of life. Your doctor or someone on your medical team is likely involved in research related to your condition.

Our patients tell us that the quality of their interactions, our attention to detail and the efficiency of their visits mean health care — and trusted answers — like they've never experienced.

Why Choose Mayo Clinic

What Sets Mayo Clinic Apart

You may have one or more of these imaging tests: magnetic resonance imaging (MRI), computerized tomography (CT), positron emission tomography (PET), nuclear medicine scans, endoscopic ultrasound of the pancreas and other scans. In tests that involve radiation, specialists carefully monitor doses to avoid the risk of radiation overexposure.

Conditions and testing related to MEN 1 may include:

  • Pituitary tumors. At Mayo Clinic, monitoring for pituitary tumors in people with MEN 1 includes an MRI of the pituitary gland and measuring certain hormones in your blood. If MRI results are abnormal, your doctor may do other pituitary testing. The most common pituitary gland problem in MEN 1 is a small tumor that releases too much prolactin (prolactinoma), which can often be treated without surgery.
  • Hyperparathyroidism. Specialists diagnose overactive parathyroid glands (hyperparathyroidism) in people with MEN 1 based on parathyroid hormone (PTH) and calcium levels. Almost all people with MEN 1 develop hyperparathyroidism. At Mayo Clinic, specialists use the latest technology for diagnosis.
  • Pancreatic and duodenal neuroendocrine tumors. Specialists may use tests to detect substances produced by tumors (tumor markers) in the blood of people with MEN 1. Sometimes these changes can be found before symptoms appear. Mayo specialists may also use endoscopic ultrasound to detect endocrine tumors in the first part of the small intestine (duodenum) and the pancreas. Nuclear medicine scans, such as octreotide scintigraphy, may be used to confirm the presence and locations of pancreatic neuroendocrine tumors.
  • Other tumors and findings. Tumors may arise in the lungs, thymus gland (carcinoid tumors) and esophagus (leiomyoma). Doctors will usually perform periodic imaging tests of these areas. People with MEN 1 often have skin tumors; these are benign and should be removed only if they cause symptoms.

Genetic consultation and testing

You and your family can meet with genetic specialists to review the pros and cons of genetic testing. At this meeting, you can learn:

  • How and where the test is performed
  • The probability of a positive test
  • How a positive test would influence current medical management
  • How a positive test would provide options for at-risk family members
  • Which family members might be at risk and need further evaluation

Genetic testing may determine whether someone has a genetic mutation related to MEN 1. If no related genetic changes are found in family members, then no further screening tests are needed. However, genetic testing doesn't uncover all MEN 1 genetic mutations. If genetic testing doesn't confirm MEN 1, but it's likely a person has it, then close follow-up with diagnostic imaging and other tests is still necessary.

Mayo Clinic experts encourage people who have a MEN 1 genetic mutation to have periodic tests to look for tumors and other related medical problems. Experts recommend that family members at risk of MEN 1 start getting clinical screening in childhood or the early teen years.

Mayo Clinic experts have a wealth of expertise in the latest interventions for primary multiple endocrine neoplasia, type 1 (MEN 1) tumors and those that have spread (metastasized). Treatment for MEN 1 depends on each person's situation and related conditions. In the early stages, specialists may recommend surgery to remove tumors as well as drug therapy to regulate hormones. If a tumor is cancerous and has spread, doctors may use surgery, radiation, chemotherapy and other treatments.

Below are examples of related conditions and treatment options:

  • Pituitary tumors. Doctors may recommend surgery or drug therapy based on the type of pituitary tumor. They will recommend regular follow-up screening.
  • Hyperparathyroidism. Most people with MEN 1 will develop too much calcium in the blood (hypercalcemia) and too much parathyroid hormone (hyperparathyroidism) by the time they reach age 50. Regular screening for people at risk can detect hyperparathyroidism much earlier. The most common treatment is surgery to remove three and a half of the four parathyroid glands (subtotal parathyroidectomy). If high blood-calcium levels return years later, doctors can use an ultrasound to find the tumor and partially destroy the remaining parathyroid tissue by injecting alcohol with a needle (ethanol ablation). Doctors may delay removing the parathyroid glands because their removal for MEN 1 rarely cures the condition.
  • Pancreatic and duodenal neuroendocrine tumors. People with MEN 1 frequently develop pancreatic and small intestine (duodenal) neuroendocrine tumors. These can become malignant, so early detection and intervention is important. Treatment depends on the type and stage of the tumor.
  • Hypoglycemic syndrome. Some people with MEN 1 develop tumors associated with too much insulin (insulinomas). Although the tumors are most often not cancerous (benign), no effective medical treatment exists, and they can cause life-threatening insulin imbalance. So doctors may recommend surgery, which usually involves removing part of the pancreas (distal pancreatectomy) and any remaining pancreatic tumors.
  • Other pancreatic endocrine tumors. People with MEN 1 who develop malignant islet cell tumors may require an aggressive approach, including surgical removal of part of the pancreas, nearby lymph nodes and any remaining tumors. A variety of treatments are available if the tumor has spread to other sites, such as the liver.
  • Zollinger-Ellison Syndrome. Many people with MEN 1 develop Zollinger-Ellison Syndrome (ZES), which involves tumors that result in overproduction of gastric acid (gastrinomas) leading to ulcers and diarrhea. Doctors may prescribe medication such as proton pump inhibitors (PPIs). However, extensive surgery may be necessary to slow the progress of the disease.
  • Advanced pancreatic disease. If your disease is more advanced — for example, if it spread to the liver — treatment may involve liver surgery and radiofrequency ablation or injecting strong chemotherapy drugs directly into the liver (chemoembolization). When surgery is not an option, doctors may use other forms of chemotherapy or hormone-based treatments.
  • Adrenal tumors. Some people with MEN 1 develop tumors in their adrenal glands. Most do not produce hormones and are not cancerous, so they can be observed. However, if the tumors produce hormones or they're large and thought to be cancerous, doctors recommend removing them.
  • Carcinoid tumors. Carcinoid tumors in people with MEN 1 can develop in the lungs, thymus gland and gastrointestinal (GI) tract. Surgeons remove these tumors when they haven't spread to other areas. Doctors may use chemotherapy, radiation therapy or hormone-based therapy for advanced cases.

Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

Specialists at Mayo Clinic in Arizona treat adults with MEN 1. Medical specialists involved in testing, diagnosis and treatment vary, depending on the symptoms and disease progression. The team may include specialists in endocrinology, general surgery, gastroenterology, neurosurgery, radiation oncology and others if needed.

For appointments or more information, call the Central Appointment Office at 800-446-2279 (toll-free) 8 a.m. to 5 p.m. Mountain Standard Time, Monday through Friday or complete an online appointment request form.

Specialists at Mayo Clinic in Florida treat adults with MEN 1. Medical specialists involved in testing, diagnosis and treatment vary, depending on the symptoms and disease progression. The team may include specialists in endocrinology, general surgery, gastroenterology, neurosurgery, radiation oncology, nuclear medicine, medical genetics and others if needed.

For appointments or more information, call the Central Appointment Office at 904-953-0853 8 a.m. to 5 p.m. Eastern time, Monday through Friday or complete an online appointment request form.

Specialists at Mayo Clinic in Minnesota treat adults and children with MEN 1. Medical specialists involved in testing, diagnosis and treatment vary, depending on the symptoms and disease progression. The team may include specialists in endocrinology, general surgery, gastroenterology, neurosurgery, radiation oncology and others if needed.

For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.

In most cases, symptoms of MEN 1 do not occur until people are in their 20s or 30s. However, at-risk children may be tested for the genetic mutation associated with MEN 1.

If test results confirm a genetic mutation, specialists at Mayo Clinic may recommend regular screening, starting between ages 10 and 15, for hyperthyroidism and other signs of the disorder. Children are most likely to have pituitary tumors or abnormalities in parathyroid hormone levels. Their treatment is similar to that of adults.

For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.

See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.

See a list of publications by Mayo doctors on multiple endocrine neoplasia, type 1 (MEN 1) on PubMed, a service of the National Library of Medicine.

Nov. 19, 2012