MEN Type 2
Multiple endocrine neoplasia type 2 (MEN2) is a rare genetic polyglandular cancer syndrome, characterized by the 100% prevalence of medullary thyroid carcinoma (MTC) and an increased risk of develop other specific tumors affecting additional glands of the endocrine system.
Other names of MEN Type 2
Causes of MEN Type 2
MEN2 is caused by a change (mutation) of the RET gene.
The RET gene is an oncogene, a gene that plays a role in the development of cancer.
When operating normally, the RET protein produced by the RET gene exerts several key functions including control of cell division and regulation of cell death (apoptosis).
Activating mutations of the RET gene lead to uncontrolled growth of cells, causing tumor formation in target organs.
- MEN2 is a dominant genetic disorder.
- A single copy of a mutated RET gene is sufficient for the appearance of the disease.
- The RET mutation may be inherited from one of the parents, or occur as a spontaneous genetic change (new mutation) that occurs randomly for no apparent reason at embryo level.
- The risk of passing the abnormal gene from affected parent to offspring is 50 percent for each pregnancy, with equal risk for male and female children.
Symptoms of MEN Type 2
MEN2 can present with a sign or symptom related to a tumor or, in the case of multiple endocrine neoplasia type 2b, with characteristic musculoskeletal and/or lip and/or gastrointestinal findings.
Medullary thyroid carcinoma (MTC) represents the most frequent initial diagnosis.
Occasionally pheochromocytoma or primary hyperparathyroidism may be the initial diagnosis.
Pheochromocytoma occurs in 33-50% of MEN2 cases.
In MEN2A, primary hyperparathyroidism occurs in 10–50% of cases and is usually diagnosed after the third decade of life.
Rarely, it may present in childhood or be the sole clinical manifestation of this syndrome.
MEN2A associates medullary thyroid carcinoma with pheochromocytoma in about 20–50% of cases and with primary hyperparathyroidism in 5–20% of cases.
MEN2B associates medullary thyroid carcinoma with pheochromocytoma in 50% of cases, with marfanoid habitus and with mucosal and digestive neurofibromatosis
Diagnosis of MEN Type 2
Affected individuals may receive a clinical diagnosis of MEN2 following a specific clinical evaluation for MEN2-associated tumors, a detailed patient and familial history and the identification of characteristic features.
A variety of tests can aid in the diagnosis of MEN2.
Such tests include those designed to detect elevated levels of certain hormones in the blood.
Identification of elevated hormones in the blood can be an indication of specific endocrine tumors.
For example, identification of elevated levels of calcitonin can indicate the presence of MTC, elevated levels of PTH can indicate the presence of a parathyroid tumor, and elevated levels of catecholamines may indicate the presence of an active PHEO.
A variety of imaging (x-ray) scans may also be performed to aid in identifying the size and specific location of tumors, and lead surgical interventions.
Treatment of MEN Type 2
Management of MEN2 patients includes thyroidectomy including cervical central and bilateral lymph nodes dissection for MTC, unilateral adrenalectomy for unilateral pheochromocytoma or bilateral adrenalectomy when both glands are involved and selective resection of pathologic parathyroid glands for primary hyperparathyroidism.
Familial genetic screening is recommended to identify at risk subjects who will develop the disease, permitting early management by performing prophylactic thyroidectomy, giving them the best chance of cure.