Multiple endocrine neoplasia type 1 (MEN 1) is a rare genetic disorder that affects the endocrine system, which includes glands that produce hormones that regulate many bodily functions. MEN 1 is inherited in an autosomal dominant pattern, which means that a person only needs to inherit one copy of the defective gene from one parent to develop the condition.

The hallmark feature of MEN 1 is the development of tumors in multiple endocrine glands, including the parathyroid glands, pituitary gland, and pancreas. The parathyroid gland tumors can cause hyperparathyroidism, which results in high levels of calcium in the blood. Pituitary gland tumors can cause hormonal imbalances that affect growth and metabolism, while pancreatic tumors can cause various hormone-related disorders such as insulinomas, gastrinomas, glucagonomas, and VIPomas.

The symptoms of MEN 1 can vary widely depending on the types and locations of the tumors. Some people may develop no symptoms, while others may experience symptoms such as abdominal pain, kidney stones, high blood pressure, fatigue, weakness, and weight loss.

There is no cure for MEN 1, but treatments are available to manage the symptoms and complications of the condition. Treatment options may include surgery to remove tumors, medications to control hormone levels, and radiation therapy. People with MEN 1 typically require lifelong monitoring and management by a team of specialists, including endocrinologists, surgeons, and genetic counselors.

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.