ESSENTIALS OF DIAGNOSIS
MEN 1: tumors of the parathyroid glands, endocrine pancreas and duodenum, anterior pituitary, adrenal, thyroid; carcinoid tumors; lipomas and facial angiofibromas.
MEN 2 (formerly MEN 2A): medullary thyroid cancer, hyperparathyroidism, pheochromocytoma, Hirschsprung disease (aganglionic megacolon).
MEN 3 (formerly MEN 2B): medullary thyroid cancer, pheochromocytoma, Marfan-like habitus, mucosal neuromas, intestinal ganglioneuroma, delayed puberty.
MEN 4: tumors of the parathyroid glands, anterior pituitary gland, adrenal gland, ovary, testicle, kidney.
Syndromes of MEN are inherited as autosomal dominant traits that cause a predisposition to the development of tumors of two or more different endocrine glands (Table 26–11). MEN syndromes are caused by different germline mutations and tumors arising when certain additional somatic mutations occur in predisposed organs. Patients with MEN should have genetic testing so that their first-degree relatives may then be tested for the specific mutation.
Table 26–11.Multiple endocrine neoplasia (MEN) syndromes: incidence of tumor types. ||Download (.pdf) Table 26–11. Multiple endocrine neoplasia (MEN) syndromes: incidence of tumor types.
|Tumor Type ||MEN 1 ||MEN 2 (MEN 2A) ||MEN 3 (MEN 2B) ||MEN 4 |
|Parathyroid ||95% ||20–50% ||Rare ||Common |
|Pancreatic ||54% || || ||Common |
|Pituitary ||42% || || ||Common |
|Medullary thyroid carcinoma || ||> 90% ||80% || |
|Pheochromocytoma ||Rare ||20–35% ||60% || |
|Mucosal and gastrointestinal ganglioneuromas || ||Rare ||> 90% || |
|Subcutaneous lipoma ||30% || || || |
|Adrenocortical adenoma ||30% || || ||Common |
|Thoracic carcinoid ||15% || || || |
|Thyroid adenoma ||55% || || ||Common |
|Facial angiofibromas and collagenomas ||85% || || || |
Multiple endocrine neoplasia type 1 (MEN 1, Wermer syndrome) is a tumor syndrome with a prevalence of 2–10 per 100,000 persons in the United States. About 90% of affected patients harbor a detectable germline mutation in the menin gene. This gene is located on the long arm of chromosome 11 (11q13). Genetic testing is able to detect the specific mutation in 60–95% of cases. If no mutation is detected, genetic linkage analysis can be done if there are several affected members in the kindred.
The presentation of MEN 1 is quite variable, even in the same kindred. Affected patients are prone to many different tumors, particularly involving the parathyroids, endocrine pancreas and duodenum, and anterior pituitary (Table 26–11). Incidental adrenal nodules are found in about 50% of affected patients but are rarely secretory. In some affected individuals, tumors may start developing in childhood, whereas in others, tumors develop late in adult life. The initial biochemical manifestations (usually hypercalcemia) can often be detected as early as age 14–18 years in patients with a MEN 1 gene mutation, although clinical manifestations usually present in the third or fourth decade.
Hyperparathyroidism is the first clinical manifestation of MEN 1 in two-thirds of affected patients, but it may present at any time of life. The hyperparathyroidism of MEN 1 is notoriously difficult ...