Makindo Medical Notes.com

Medullary thyroid cancer characterised by stromal amyloid is seen in almost all patients

About

• MEN2A, which affects 60% to 90% of MEN2 families
• MEN2B, which affects 5% of MEN2 families
• Rare 1 in 30,000

Aetiology

• MEN2 is associated with the RET gene
• Autosomal dominant
• Some are deNovo mutations

Clinical

• Type 2 A
  • Thyroid: Medullary thyroid cancer: 98% to 100% with MEN2A are affected
  • Adrenal: Phaeochromocytoma, a typically benign (non-cancerous) tumour of the adrenal glands: 50% with MEN2A affected
  • Parathyroid: Parathyroid adenoma (benign tumour ) or hyperplasia, meaning increased size, of the parathyroid gland: 5% to 10% with MEN2A affected
• Type 2B (Marfanoid)
  • Medullary thyroid cancer: 98% to 100%
  • Phaeochromocytoma: 50%
  • Mucosal neuromas: benign tumour of nerve tissue on the tongue, lips and throughout the gastrointestinal tract: 95% to 98% affected
  • Digestive problems caused by disordered nerves in the gastrointestinal tract: 75% to 90% affected
  • Muscle, joint, and spinal problems: 95% affected
  • Facial features, including swollen lips and thick eyelids: 75% to 90% affected

Investigations

• U&E, Calcium/Parathyroid hormone
• Urinary catecholamines/metanephrines annually beginning in childhood (MEN2A, MEN2B)
• Abdominal CT/MRI to detect phaeochromocytomas, every 4 to 5 years or when abnormal catecholamine or metanephrine levels are detected.
• Raised Ca, Normal PTH suggests hyperparathyroidism which can be resected
• Genetic testing for RET mutations which allows earlier treatments

Management

• Prophylactic thyroidectomy: If a RET mutation is found, the thyroid gland should be surgically removed to prevent cancer from developing. This applies even to young children and operations can happen before age of 3.
• Check Yearly Ca/PTH to watch for hypoparathyroidism
• Medullary Thyroid cancer: Surgical resection (removal) of thyroid and lymph nodes in the neck and upper chest.
• Phaeochromocytoma associated with MEN2 is almost always a benign tumour . Can be removed surgically with careful BP control.
• Hyperparathyroidism which can be resected

References