To diagnose multiple endocrine neoplasia, type 1 (MEN 1), your doctor will perform a physical exam and review your medical history and family history. You may have a blood test and imaging tests, including the following:

  • Magnetic resonance imaging (MRI).
  • Computerized tomography (CT) scan.
  • Positron emission tomography (PET) scan.
  • Nuclear medicine scans.
  • Endoscopic ultrasound of the pancreas and other scans.

Genetic testing may determine whether someone has a genetic change that causes MEN 1. If so, that person's children are at risk of inheriting the same genetic change and developing MEN 1. Parents and siblings also are at risk of having the genetic change that causes MEN 1.

If no related genetic changes are found in family members, then no further screening tests are needed. However, genetic testing cannot identify all the genetic changes that can cause MEN 1. If genetic testing doesn't confirm MEN 1, but it's likely a person has it, that person, as well as family members, still needs close follow-up with appropriate blood tests and diagnostic imaging.


In MEN 1, tumors can grow on the parathyroids, pancreas and pituitary gland. These tumors can lead to various conditions, all of which can be treated. These conditions and treatments may include:

  • Pituitary tumors. These types of tumors may be treated with surgery or drug therapy.
  • Hyperparathyroidism. Surgery to remove most of the parathyroid glands is the usual treatment for too much parathyroid hormone.
  • Neuroendocrine tumors. These are usually located in the pancreas or small intestine (duodenum). Treatment depends on the type and stage of the tumor.
  • Hypoglycemic syndrome. This condition results when tumors produce too much insulin (insulinomas), causing severely low levels of glucose, which can be life-threatening. Doctors usually recommend surgery and possibly removal of a portion of the pancreas.
  • Zollinger-Ellison syndrome (ZES). ZES can result in tumors that overproduce gastric acid (gastrinomas), leading to ulcers and diarrhea. Doctors may prescribe medication or surgery.
  • Other pancreatic neuroendocrine tumors. These tumors sometimes produce other hormones that can cause various health issues. Treatment of these types of tumors may involve medication, surgery or an ablation procedure. In an ablation procedure your doctor destroys abnormal tissue that may be present.
  • Metastatic neuroendocrine tumors. Disease that has spread to the lymph nodes or liver may be treated with surgery. Surgery options include liver surgery, radiofrequency ablation, cryoablation or chemoembolization.

    Radiofrequency ablation uses high-frequency energy that passes through a needle and causes the surrounding tissue to heat up, killing the nearby cells. Cryoablation involves freezing tumors. And chemoembolization involves injecting strong chemotherapy drugs directly into the liver. When surgery isn't an option, doctors may use other forms of chemotherapy or hormone-based treatments.

  • Adrenal tumors. Most of these tumors can be observed and not treated. However, if the tumors produce hormones or they're large and thought to be cancerous, doctors recommend removing them, usually with minimally invasive surgery.
  • Carcinoid tumors. Carcinoid tumors in people with MEN 1 can develop in the lungs, thymus gland and digestive 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.

Multiple endocrine neoplasia, type 1 (MEN 1) care at Mayo Clinic

Feb. 14, 2024
  1. Jameson JL, et al., eds. Multiple endocrine neoplasia type 1. In: Endocrinology: Adult and Pediatric. 7th ed. Saunders Elsevier; 2016. https://www.clinicalkey.com. Accessed Oct. 11, 2020.
  2. Melmed S, et al. Multiple endocrine neoplasia. In: Williams Textbook of Endocrinology. 14th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Oct. 11, 2020.
  3. Multiple endocrine neoplasia type 1. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/endocrine-diseases/multiple-endocrine-neoplasia-type-1. Accessed Oct. 11, 2020.
  4. Warner K. Allscripts EPSi. Mayo Clinic. Oct. 26, 2020.
  5. Multiple endocrine neoplasia, type 1 (MEN 1). Merck Manual Professional Version. https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/multiple-endocrine-neoplasia-men-syndromes/multiple-endocrine-neoplasia,-type-1-men-1. Accessed Oct. 11, 2020.
  6. Arnold A. Multiple endocrine neoplasia type 1: Treatment. https://www.uptodate.com/contents/search. Accessed Oct. 11, 2020.
  7. Kearns AE (expert opinion). Mayo Clinic. Oct. 30, 2020.
  8. Kamilaris CDC, et al. Multiple endocrine neoplasia type 1 (MEN1): An update and the significance of early genetic and clinical diagnosis. Frontiers in Endocrinology. 2019; doi: 10.3389/fendo.2019.00339.


Products & Services