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Difficulty: MediumBreast and Endocrine Surgery

A 3232-year-old man comes to the clinic for follow-up. He has a history of medullary thyroid carcinoma, for which he underwent a total thyroidectomy with central lymph node dissection three years ago. Recent surveillance imaging revealed a newly developed 4.54.5-cm right adrenal mass. The patient reports experiencing episodic headaches, excessive sweating, and palpitations over the past three months. His temperature is 37.1∘37.1^\circ C, blood pressure is 170/105170/105 mm Hg, and pulse is 112112/min. Physical examination is unremarkable. Laboratory evaluation demonstrates significantly elevated 2424-hour urine fractionated metanephrines and normetanephrines. A laparoscopic right adrenalectomy is planned. Which of the following is the most appropriate next step in the management of this patient?

  1. Initiation of phenoxybenzamine therapyAnswer
  2. B
    Initiation of propranolol therapy
  3. C
    Immediate laparoscopic right adrenalectomy
  4. D
    Image-guided percutaneous core biopsy of the mass
  5. E
    Measurement of serum thyroid-stimulating hormone (TSH) level

Answer

Initiation of phenoxybenzamine therapy
The correct answer involves initiating alpha-adrenergic blockade. This patient's clinical presentation (episodic headaches, sweating, palpitations, hypertension) combined with a history of medullary thyroid cancer and an adrenal mass is classic for a pheochromocytoma associated with Multiple Endocrine Neoplasia type 2A (MEN2A). Pheochromocytomas secrete high levels of catecholamines (epinephrine and norepinephrine), which cause profound alpha-adrenergic mediated vasoconstriction, leading to chronic intravascular volume depletion and hypertension. Before surgical resection (adrenalectomy), patients must undergo preoperative medical optimization to prevent lethal intraoperative hemodynamic instability. The standard of care is to initiate a nonselective, irreversible alpha-adrenergic antagonist, such as phenoxybenzamine, 1010 to 1414 days prior to surgery. This normalizes blood pressure and allows the intravascular volume to expand.

Step-by-Step Solution

1
Identify the patient's underlying syndrome and current diagnosis based on history and labs.
History of medullary thyroid cancer plus a new catecholamine-secreting adrenal mass (elevated metanephrines, headaches, palpitations) indicates a pheochromocytoma in the context of Multiple Endocrine Neoplasia type 2A (MEN2A).
Establishing the correct diagnosis dictates the surgical and preoperative approach.
2
Determine the required preoperative management for surgical resection of a pheochromocytoma.
The patient must receive alpha-adrenergic blockade (phenoxybenzamine) for 1010 to 1414 days prior to adrenalectomy.
Alpha-blockade prevents intraoperative hypertensive crisis during anesthesia induction and tumor manipulation, and allows for expansion of the chronically constricted intravascular volume.

Key Concept

Preoperative optimization for pheochromocytoma requires nonselective alpha-adrenergic blockade (e.g., phenoxybenzamine) BEFORE beta-adrenergic blockade to prevent unopposed alpha-receptor stimulation and hypertensive crisis.
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Topics

Breast and Endocrine Surgery

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