Multiple Endocrine Neoplasia Syndromes

Multiple endocrine neoplasia syndromes are a bunch of inherited conditions that are rare and require specialized care. These syndromes can affect multiple organ systems and can cause cancers. These can cause tumors on one or more endocrine glands and hence produce the respective hormones from the glands in excess quantity. These tumors can be benign or cancerous.

Types of Multiple Endocrine Neoplasia

1. MEN 1/Wermer Syndrome-
   • It is Chr 11q13 defect.
   • It involves the MEN-1 gene mutation that is responsible for development of menin causing uncontrolled mitosis in the endocrine glands.
   • It involves the pituitary, Pancreatic, and Parathyroid glands adenoma.
   • Pituitary Adenoma
   • It is a form of prolactinoma.
   • The female patient complained of amenorrhea and infertility.

• Pancreatic Adenoma
  • It consists of Gastrinoma or Zollinger-Ellison syndrome. Insulinoma is the most common functioning adenoma. However, the pancreatic adenoma which is not functional is more common.
  • Peptic ulcer disease in duodenum is another cause and recurrent peptic ulcer disease perforates or bleeds causing perforation peritonitis.
  • Peptic ulcer disease is the leading cause of death in type 1.
• Parathyroid Adenoma
  • It is the most common manifestation and it causes increase in parathyroid hormone and calcium level, that leads to damage to the tubular kidney.
•   It presents with recurrent nephrolithiasis, polyurea, polydipsia, and Constipation.
  • All of four parathyroid glands should be affected, and total/subtotal parathyroid resection is done.

2. Men 2A syndrome

• It is due to a defect in chromosome 10.
• The main reason for this syndrome is RET gene mutation.
• It includes-
  • Parathyroid adenoma
  • Phaeochromocytoma
  • Medullary thyroid adenoma
• Parathyroid Adenoma-
  • It is the most common presentation.
  • The calcium values can be normal in more than 50% of cases.
• Phaeochromocytoma
  • It is the major diagnostic criteria for men 2 and men 3.
  • There is an increase in catecholamines and that leads to poorly controlled hypertension.
  • It is the leading cause of death in men too.
• Medullary Thyroid Carcinoma-
  • In this type of carcinoma, there is an increase in a number of calcitonin levels.
  • It is the only tumor marker for medullary thyroid carcinoma.
  • An increase in calcitonin will not cause hypocalcemia.
  • The patient will present with a lump in the neck.
  • On a thyroid scan, there is the presence of old nodules and on a PET scan, there is evidence of metastasis.

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Clinical Presentation of Medullary Thyroid Carcinoma

• The patient is usually asymptomatic but later on, it can become symptomatic.
• Neck mass will be seen and the patient will have symptoms of dysphagia.
• Due to an increase in calcitonin and serotonin, there will be diarrhea.
• Calcium levels will be normal in more than 50% of cases.
• It is normally associated with congenital aganglionosis and Hirschsprung disease.
• It is managed by prophylactic thyroidectomy.
• It increases the lifespan of an individual with a lifelong thyroxine replacement.

3. Men3/2B Syndrome

• It includes-
  • Medullary thyroid carcinoma-

1. It is the most common presentation of MEN 2B.
   • Normal calcium levels will be present period
2. It consists of pheochromocytoma which is the leasing leading cause of death in MEN 3 type or MEN 2B.
3. To learn the criteria. Remember M4 mnemonic-
   • Marfanoid habitus
   • Mucosal neuromas
   • Medullated Corneal Fibres
   • Megacolon
4. MEN4
   • It is due to a mutation in the CDKN1B gene.
   • It involves mainly-
     • Pituitary Adenoma in the form of prolactinoma.
     • Parathyroid Adenoma- Hypercalcemia is the main manifestation.
     • Reproductive tract tumors like testicular tumors and neuroendocrine tumors of the cervix.
     • It is may or may not associated with the adrenal or renal tumor.

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