From the Guidelines
Multiple endocrine neoplasia (MEN) syndromes that involve both the thyroid and pancreas are primarily MEN1 and MEN2, with MEN1 affecting the parathyroid glands, pancreas, and pituitary gland, and MEN2 characterized by medullary thyroid carcinoma in nearly all patients, with some developing pheochromocytomas and parathyroid hyperplasia 1.
Key Characteristics of MEN1 and MEN2
- MEN1:
- Affects parathyroid glands, pancreas, and pituitary gland
- Pancreatic neuroendocrine tumors occur in 40-75% of patients
- Thyroid adenomas occur in a smaller percentage of patients
- MEN2:
- Characterized by medullary thyroid carcinoma in nearly all patients
- Some patients develop pheochromocytomas and parathyroid hyperplasia
Management and Treatment
- Management requires a multidisciplinary approach with regular screening, including annual thyroid ultrasounds, calcitonin measurements, and pancreatic imaging
- Treatment typically involves surgical removal of thyroid tumors (total thyroidectomy for MEN2) and pancreatic lesions when indicated
- Post-thyroidectomy, lifelong thyroid hormone replacement with levothyroxine (typically 1.6-1.8 mcg/kg/day) is necessary
Genetic Mutations and Inheritance Patterns
- MEN1 is caused by MEN1 gene mutations and follows an autosomal dominant inheritance pattern
- MEN2 is caused by RET proto-oncogene mutations and also follows an autosomal dominant inheritance pattern
- Genetic testing and family screening are essential components of management, as these syndromes can be inherited by family members 1.
Importance of Early Detection and Intervention
- Early detection and intervention can decrease mortality and morbidity associated with these tumors
- Pre-symptomatic screening of at-risk patients can allow for earlier detection and intervention, reducing the risk of hormonal hypersecretion and related symptoms 1.
From the Research
Multiple Endocrine Neoplasia (MEN) Syndrome Involving Thyroid and Pancreas
- MEN1 and MEN2 are hereditary cancer syndromes that affect various endocrine glands, including the thyroid and pancreas 2.
- The commonest tumors in MEN1 secrete PTH or gastrin, while in MEN2, they secrete calcitonin or catecholamines 2.
- Management strategies for MEN1 and MEN2 have improved with the discovery of their respective genes, allowing for earlier diagnosis and treatment 2.
Thyroid Involvement in MEN Syndrome
- Thyroidectomy is a crucial treatment for MEN2 carriers to prevent or cure medullary thyroid cancer (MTC) 2.
- The specific RET codon mutation correlates with the MEN2 syndromic variant, age of onset of MTC, and aggressiveness of MTC, guiding major management decisions 2.
Pancreas Involvement in MEN Syndrome
- Entero-pancreatic endocrine tumors are common in MEN1, and their management involves biochemical tests, imaging tests, and surgery in some cases 2, 3.
- Proton pump inhibitors or somatostatin analogs are used to manage oversecretion of entero-pancreatic hormones, except insulin 2.
Diagnosis and Treatment of MEN Syndrome
- Genetic testing for MEN1 and RET mutations can provide useful information for diagnosis and management 2, 4.
- Parathyroidectomy is often necessary for MEN1 patients with primary hyperparathyroidism, and the timing of surgery depends on various factors, including age and severity of symptoms 3, 4.
- Multimodality imaging is essential for diagnosing and monitoring MEN-related tumors, including those in the thyroid and pancreas 5.