The multiple endocrine neoplasia (MEN) syndromes comprise 4 genetically distinct familial diseases involving adenomatous hyperplasia and malignant tumors in several endocrine glands.
MEN 1 Multiple Endocrine Neoplasia, Type 1 (MEN 1) Multiple endocrine neoplasia, type 1 (MEN 1) is an autosomal dominant syndrome characterized by hyperplasia or adenomas of the parathyroid glands, pancreatic islet cell tumors (also known as... read more involves primarily hyperplasia or sometimes adenomas of the parathyroid glands (with resultant hyperparathyroidism Primary hyperparathyroidism Hypercalcemia is a total serum calcium concentration > 10.4 mg/dL (> 2.60 mmol/L) or ionized serum calcium > 5.2 mg/dL (> 1.30 mmol/L). Principal causes include hyperparathyroidism... read more ) and tumors of the pancreatic islet cells and/or pituitary gland.
MEN 2A Multiple Endocrine Neoplasia, Type 2A (MEN 2A) Multiple endocrine neoplasia, type 2A (MEN 2A) is an autosomal dominant syndrome characterized by medullary carcinoma of the thyroid, pheochromocytoma, parathyroid hyperplasia or adenomas (causing... read more
involves primarily medullary thyroid carcinoma Medullary Thyroid Carcinoma There are 4 general types of thyroid cancer. Most thyroid cancers manifest as asymptomatic nodules. Rarely, lymph node, lung, or bone metastases cause the presenting symptoms of small thyroid... read more , pheochromocytoma Pheochromocytoma A pheochromocytoma is a catecholamine-secreting tumor of chromaffin cells typically located in the adrenals. It causes persistent or paroxysmal hypertension. Diagnosis is by measuring catecholamine... read more , hyperplasia or sometimes adenomas of the parathyroid glands Parathyroid adenoma Most parathyroid tumors are benign. Parathyroid tumors secrete parathyroid hormone (PTH). Elevated parathyroid hormone levels ( hyperparathyroidism) causes hypercalcemia. Parathyroid adenomas... read more (with resultant hyperparathyroidism), and occasionally cutaneous lichen amyloidosis.MEN 2B Multiple Endocrine Neoplasia, Type 2B (MEN 2B) Multiple endocrine neoplasia, type 2B (MEN 2B) is an autosomal dominant syndrome characterized by medullary thyroid carcinoma, pheochromocytoma, multiple mucosal neuromas and intestinal ganglioneuromas... read more
involves primarily medullary thyroid carcinoma, pheochromocytoma, multiple mucosal and intestinal neuromas, and marfanoid habitus.MEN 4 Multiple Endocrine Neoplasia, Type 4 (MEN 4) Multiple endocrine neoplasia, type 4 (MEN 4) is an autosomal dominant syndrome characterized by adenomas and sometimes hyperplasia of the parathyroid glands and tumors of the pancreatic islet... read more involves primarily adenomas and sometimes hyperplasia of the parathyroid glands (with resultant hyperparathyroidism Primary hyperparathyroidism Hypercalcemia is a total serum calcium concentration > 10.4 mg/dL (> 2.60 mmol/L) or ionized serum calcium > 5.2 mg/dL (> 1.30 mmol/L). Principal causes include hyperparathyroidism... read more ) and tumors of the pancreatic islet cells and/or pituitary gland.
Clinical features depend on the glandular elements involved. The phenotype of MEN 4 is similar to that of MEN 1 but lacks the cutaneous abnormalities seen in the latter disorder.
Each syndrome is inherited as an autosomal dominant trait with a high degree of penetrance, variable expressivity, and production of seemingly unrelated effects by a single mutant gene. The specific mutation is not always known.
Symptoms and signs develop at any age. Proper management includes early identification of affected individuals within a kindred and surgical removal of the tumors when possible. Although these syndromes are genetically and clinically distinct, significant overlap exists (see table ).
