Is a biopsy recommended for a patient with suspected pheochromocytoma?

Biopsy of Pheochromocytoma: Not Recommended

Biopsy of suspected pheochromocytoma is contraindicated due to the high risk of triggering a potentially fatal hypertensive crisis. 1

Diagnostic Approach for Suspected Pheochromocytoma

The proper diagnostic approach for pheochromocytoma follows a specific sequence:

1. Biochemical confirmation first

   • Plasma free metanephrines is the preferred initial test (99% sensitivity, 89% specificity) 1, 2
   • 24-hour urine collection for fractionated metanephrines is an alternative (97% sensitivity) 1, 2
   • Levels typically >4 times the upper limit of normal in true pheochromocytoma 1

2. Imaging only after biochemical confirmation

   • MRI is preferred over CT if pheochromocytoma is strongly suspected due to risk of hypertensive crisis with IV contrast 1
   • Adrenal protocol CT or MRI should be performed to evaluate for adrenal masses 1
   • Whole-body imaging from skull base to pelvis for suspected paraganglioma 1

3. Additional functional imaging if needed

   • Meta-iodobenzylguanidine (MIBG) scintigraphy if conventional imaging is negative 1
   • FDOPA-PET for detection of pheochromocytomas in hereditary syndromes 1

Why Biopsy is Dangerous

Pheochromocytomas are highly vascular tumors that secrete catecholamines. Manipulation during biopsy can trigger:

• Massive catecholamine release leading to hypertensive crisis
• Potentially fatal arrhythmias
• Stroke or myocardial infarction
• Tumor rupture and seeding

Clinical Presentation to Consider

Pheochromocytoma should be suspected in patients with:

• Paroxysmal hypertension (may be sustained in up to 50% of cases) 3
• Classic triad: headaches, palpitations, and sweating 1
• Resistant hypertension (prevalence up to 4% in referred RH patients) 3
• Family history of pheochromocytoma or related genetic syndromes 1
• Incidentally discovered adrenal mass

Preoperative Management

Once diagnosed, proper preparation before surgical removal includes:

• Alpha-adrenergic blockade should be started if normetanephrine levels are ≥2-fold the upper reference limit 1
• Options include:
  • Non-selective α-blocker: Phenoxybenzamine (40-80 mg/day)
  • Selective α1-blockers: Doxazosin, prazosin, or terazosin 1
• Beta-blockers should only be added after adequate alpha-blockade 1
• Calcium channel blockers can be added if target blood pressure is not achieved 1

Surgical Approach

• Complete surgical resection is the definitive treatment 1
• Laparoscopic adrenalectomy for small tumors (<8 cm) without invasion
• Open surgery for larger tumors (>5-6 cm) or with evidence of invasion 1
• Surgery should be performed in specialized centers with experience in adrenalectomy 1

Key Pitfalls to Avoid

1. Never perform a biopsy of suspected pheochromocytoma
2. Never proceed to imaging without biochemical confirmation first
3. Never start beta-blockers before adequate alpha blockade (can worsen hypertension)
4. Never miss genetic testing (approximately 40% of cases are hereditary) 4, 5
5. Never discharge without planning lifelong follow-up (recurrences can occur decades later) 6

The diagnostic approach to pheochromocytoma requires careful sequencing of tests, with biochemical confirmation always preceding any invasive procedures. Biopsy should be avoided entirely due to the significant risk of triggering a potentially fatal hypertensive crisis.