Multiple endocrine neoplasia type 1 (MEN1)
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A 35-year-old woman presents with recurrent kidney stones and is found to have elevated calcium and PTH. Further workup reveals a prolactinoma on brain MRI. Her father had a pancreatic neuroendocrine tumor resected at age 40.
AD; MEN1 (menin, tumor suppressor on chromosome 11q13)
- ~10% de novo
- High penetrance (~95% by age 40)
- Loss of heterozygosity (LOH) at tumor sites
The 3 Ps:
- Parathyroid adenomas (>90%): most common and usually earliest manifestation; primary hyperparathyroidism
- Pituitary adenomas (~40%): prolactinoma most common; also GH-secreting, ACTH-secreting
- Pancreatic neuroendocrine tumors (~60%): gastrinoma (Zollinger-Ellison syndrome), insulinoma, non-functioning
Other tumors:
- Adrenal cortical tumors (~25%)
- Facial angiofibromas, collagenomas
- Thymic/bronchial carcinoids
- Genetic testing for MEN1 pathogenic variants
- Clinical diagnosis: ≥2 of the 3 Ps, or 1 of the 3 Ps plus a first-degree relative with MEN1
- Biochemical screening starting by age 8 in at-risk family members
- Annual calcium/PTH, prolactin, fasting glucose/insulin, gastrin
- Periodic imaging (MRI pituitary, CT/MRI abdomen)
- Parathyroidectomy for hyperparathyroidism
- Tumor-specific surgical and medical management
3 Ps of MEN1: Parathyroid, Pituitary, Pancreas