A 55-year-old man with MEN2A syndrome is found to have a 1.2 cm medullary thyroid carcinoma on neck ultrasound. Basal serum calcitonin is 320 pg/mL. Prior to thyroid surgery, the FIRST investigation/intervention that must be performed is:
- A Sestamibi scan to localise parathyroid adenoma
- B Pentagastrin stimulation test to confirm calcitonin elevation
- C 24-hour urinary catecholamines and metanephrines to exclude phaeochromocytoma ✓
- D Fine needle aspiration cytology of the thyroid nodule
Correct answer: C. 24-hour urinary catecholamines and metanephrines to exclude phaeochromocytoma
Explanation
In MEN2A, phaeochromocytoma co-exists in 50% of patients and must be excluded and treated BEFORE thyroid or parathyroid surgery to prevent a potentially lethal hypertensive crisis induced by anaesthesia/surgery. Sestamibi is done to plan parathyroid surgery but is done after phaeochromocytoma exclusion. Pentagastrin stimulation is unnecessary when basal calcitonin is already elevated. FNAC is not required when medullary carcinoma is strongly suspected in a MEN2A context with elevated calcitonin.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.