Multiple Endocrine Neoplasia

• Autosomal dominant
• MEN-1
  • Pituitary adenoma
    • Visual field defects
    • Headaches
    • Diplopia (oculomotor nerve compression from lateral extension of adenoma)
    • Hormone deficiencies from compression of non-functioning adenomas
      • Decreased libido / fertility (hypogonadotropic hypogonadism)
      • Cold intolerance, lethargy (hypothyroidism)
      • Lethargy, postural dizziness (hypoadrenalism)
      • Galactorrhoea (excess prolactin)
    • Hormone excess (functioning pituitary adenoma)
      • Acromegaly
      • Cushing’s disease
      • Galactorrhoea, amenorrhoea, erectile dysfunction (prolactinoma)
      • Thyrotroph, gonadotroph adenomas are very rare
  • Parathyroid adenoma (hypercalcaemia)
    • Polydipsia
    • Polyuria
    • Constipation
    • Renal colic from renal stones
    • Depression
  • Pancreatic neoplasm
    • Peptic ulcer disease (Zollinger-Ellison syndrome)
    • Diarrhoea (VIPoma)
    • Recurrent hypoglycaemia (insulinoma)
• MEN -2
  • Autosomal dominant
  • Medullary thyroid carcinoma
    • Solitary thyroid nodule
    • Cervical lymphadenopathy
    • May cause ectopic ACTH secretion
    • Thyroid function tests are normal in patients with MTC
  • Phaeochromocytoma
    • Headaches
    • Sweating
    • Palpitations
    • Hypertension
  • MEN-2a: parathyroid adenoma
  • MEN-2b: Marfanoid habitus

Investigations and management

• Anterior pituitary hormone screen
  • Cortisol (first), thyroxine (second), testosterone replacement if depressed
• Magnetic resonance imaging of the brain looking for pituitary adenoma
  • Trans-sphenoidal resection of the pituitary
• Serum calcium and PTH measurement
  • Parathyroidectomy
• Radioiodine uptake scan – cold nodule in MTC, fine-needle aspiration
  • Thyroidectomy
• Phaeochromocytoma: serum metanephrines, 24hr urinary metanephrines
  • α blockade (phenoxybenzamine) → β blockade, then definitive surgery