What is the appropriate management for a patient with pheochromocytoma?

Management of Pheochromocytoma

Complete surgical resection (R0) is the mainstay of potentially curative treatment for pheochromocytoma, with mandatory preoperative alpha-adrenergic blockade for at least 10-14 days before surgery to prevent perioperative complications. 1, 2

Diagnosis and Initial Evaluation

• Biochemical testing must precede imaging:

  • First-line test: Plasma free metanephrines (sensitivity 96-100%, specificity 89-98%)
  • Alternative: 24-hour urinary fractionated metanephrines (sensitivity 86-97%, specificity 86-95%)
  • Collect plasma samples after patient has been lying supine for 30 minutes 2

• Imaging (only after biochemical confirmation):

  • CT scan of abdomen is first-line imaging modality
  • MRI is an alternative option
  • Functional imaging (MIBG scanning or FDOPA-PET) for suspected metastatic disease 2

Preoperative Management

Alpha-Adrenergic Blockade (10-14 days before surgery)

• Options include:

  • Non-selective α-blocker: Phenoxybenzamine
  • Selective α1-blocker: Doxazosin, prazosin, or terazosin 1
  • Start with low dose and gradually increase every 2-4 days 1

• Blood pressure targets:

  • <130/80 mmHg in supine position
  • Systolic BP >90 mmHg in upright position 1

Additional Preoperative Measures

1. Beta-blockers: Only add after adequate alpha-blockade if tachyarrhythmias develop (never start before alpha-blockade) 1, 2

2. Calcium channel blockers: Can be used as adjunct therapy for refractory hypertension or as alternative to alpha-blockers 1, 3

3. Metyrosine (alpha-methyl-p-tyrosine):

   • Inhibits tyrosine hydroxylase, reducing catecholamine synthesis by 35-80%
   • Can be used in combination with alpha-blockers for better blood pressure control
   • Particularly useful for patients with severe disease 4, 5, 6

4. Volume expansion:

   • High-sodium diet
   • 1-2 liters saline infusion 24 hours before surgery
   • Compressive stockings to reduce orthostatic hypotension 2

Surgical Management

• Surgical approach:

  • Laparoscopic adrenalectomy for small tumors (<8 cm) without invasiveness 1
  • Open surgery for larger tumors or those with evidence of invasion
  • Include locoregional lymphadenectomy to improve staging and outcomes 1, 2

• Perioperative monitoring:

  • Close hemodynamic monitoring during surgery
  • Have medications readily available to treat hypertensive crisis:
    • Magnesium sulfate
    • Phentolamine
    • Nitroprusside
    • Nitroglycerin 1

Special Situations

Malignant Pheochromocytoma

• Cytoreductive (R2) surgery may improve quality of life and survival by reducing tumor burden and controlling hormonal hypersecretion 1
• Metyrosine is indicated for chronic treatment of malignant pheochromocytoma 4

Pregnancy

• If diagnosed within first 24 weeks: Laparoscopic adrenalectomy after 10-14 days of alpha-blockade
• If diagnosed in third trimester: Medical management until fetus is viable, then cesarean section with tumor removal in same session 1

Follow-up

• Immediate post-operative:

  • Measure plasma/urine metanephrines by 8 weeks post-treatment
  • Imaging at 3-6 months post-surgery 1, 2

• Long-term follow-up:

  • Continue for at least 10 years
  • Every 3-4 months for 2-3 years, then every 6 months
  • Lifelong surveillance recommended for patients with genetic syndromes, extra-adrenal disease, tumor size >5 cm 1, 2

Common Pitfalls and Caveats

1. Never start beta-blockers before alpha-blockers - can worsen hypertension due to unopposed alpha-stimulation

2. Avoid biopsy of suspected pheochromocytoma - risk of precipitating hypertensive crisis

3. Don't rely solely on blood pressure for diagnosis - hypertension may be paroxysmal or even absent in some cases

4. Beware of medications that can interfere with testing - tricyclic antidepressants, certain antipsychotics, and sympathomimetics can cause false positives

5. Don't underestimate the importance of genetic testing - approximately 25% of pheochromocytomas are hereditary 2

6. Avoid delays in diagnosis and treatment - average delay in diagnosis is 3 years, which increases morbidity and mortality 2