MEN I is caused by a defect in a gene that carries the code for a protein called menin. The condition causes tumors of various glands to appear in the same person, but not necessarily at the same time.
The disorder may occur at any age, and it affects men and women equally. A family history of this disorder raises your risk.
Multiple endocrine neoplasia (MEN) type I is a disease in which one or more of the endocrine glands are overactive or forms a tumor. It is passed down through families.
Endocrine glands most commonly involved include:
Exams and Tests
The health care provider will perform a physical exam and ask questions about your medical history and symptoms. The following tests may be done:
- Blood cortisol level
- CT scan of the abdomen
- CT scan of the head
- Fasting blood sugar
- Genetic testing
- Insulin test
- MRI of the abdomen
- MRI of the head
- Parathyroid biopsy
- Serum adrenocorticotropic hormone
- Serum calcium
- Serum follicle stimulating hormone
- Serum gastrin
- Serum glucagon
- Serum luteinizing hormone
- Serum parathyroid hormone
- Serum prolactin
- Serum thyroid stimulating hormone
- Ultrasound of the neck
Pituitary and parathyroid tumors are usually noncancerous (benign), but some pancreatic tumors may become cancerous (malignant) and spread to the liver. These can lower life expectancy.
The symptoms of peptic ulcer disease, low blood sugar, excess calcium in the blood, and pituitary dysfunction usually respond well to appropriate treatment.
The tumors can keep coming back. Symptoms and complications depend on which glands are involved. Regular check-ups by your provider are essential.
Screening close relatives of people affected with this disorder is recommended.
Symptoms vary from person to person, and depend on which gland is involved. They may include:
- Abdominal pain
- Black, tarry stools
- Bloated feeling after meals
- Burning, aching, or hunger discomfort in the upper abdomen or lower chest that is relieved by antacids, milk, or food
- Decreased sexual interest
- Lack of menstrual periods (in women)
- Loss of appetite
- Loss of body or facial hair (in men)
- Mental changes or confusion
- Muscle pain
- Nausea and vomiting
- Sensitivity to the cold
- Unintentional weight loss
- Vision problems
Surgery to remove the diseased gland is often the treatment of choice. A medicine called bromocriptine may be used instead of surgery for pituitary tumors that release the hormone prolactin.
The parathyroid glands, which control calcium production, can be removed. However, it is difficult for the body to regulate calcium levels without these glands, so a total parathyroid removal is not done first in most cases.
Medicine is available to decrease the excess stomach acid production caused by some tumors (gastrinomas), and to reduce the risk of ulcers.
Hormone replacement therapy is given when entire glands are removed or do not produce enough hormones.
When to Contact a Medical Professional
Call your provider if you notice symptoms of MEN I or have a family history of this condition.
Marx SJ, Wells SA. Multiple endocrine neoplasia. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier; 2016:chap 39.
National Comprehensive Cancer Network website. Clinical practice guidelines in oncology (NCCN guideines): neuroendocrine tumors. Version 3.2017.
Nieman LK, Spiegel AM. Polyglandular disorders. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 231.
Thakker RV. Multiple endocrine neoplasia type 1. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 148.