What is the initial approach to managing adrenal incidentalomas?

Initial Approach to Managing Adrenal Incidentalomas

For all adrenal incidentalomas, initial management should include dedicated adrenal imaging and comprehensive hormonal evaluation, regardless of imaging appearance. 1

Diagnostic Evaluation

Imaging Assessment

1. Initial imaging characterization:

   • Determine if the mass has benign features:
     • Homogeneous appearance
     • Low attenuation (<10 Hounsfield Units) on non-contrast CT
     • Size <4 cm
     • Well-defined margins 1

2. Second-line imaging (for indeterminate lesions):

   • Contrast-enhanced CT with washout study (>60% washout at 15 minutes suggests benign lesion)
   • Chemical-shift MRI (particularly useful with CT contrast contraindications)
   • FDG-PET for distinguishing potentially malignant lesions 1

Hormonal Evaluation

All adrenal incidentalomas require hormonal testing regardless of imaging appearance 1:

1. Mandatory tests for all patients:

   • 1-mg overnight dexamethasone suppression test (cortisol ≤50 nmol/L or 1.8 µg/dL indicates normal suppression) 2
   • Plasma or 24-hour urinary metanephrines (for pheochromocytoma) 1

2. For patients with hypertension:

   • Aldosterone-to-renin ratio (for primary aldosteronism) 1

Management Algorithm

For Benign-Appearing, Non-Functioning Masses:

• <4 cm with definitive benign imaging features:

  • No further follow-up imaging required 1

• ≥4 cm with benign features:

  • Repeat imaging in 6-12 months 1
  • Consider surgical removal due to increased malignancy risk 3

For Indeterminate Masses:

• Repeat imaging in 3-12 months 4
• If growth >5 mm/year: Consider adrenalectomy after repeating functional workup 1
• If growth <3 mm/year: No further imaging or functional testing required 1

For Functioning Masses (regardless of size):

• Cortisol-secreting adenomas: Laparoscopic adrenalectomy with perioperative steroid coverage 1
• Aldosterone-secreting adenomas: Laparoscopic adrenalectomy 1
• Pheochromocytoma: Surgical removal with appropriate preoperative alpha-blockade 1
• Mild autonomous cortisol secretion: Consider adrenalectomy if progressive metabolic comorbidities are present 2

For Suspicious/Malignant Features:

• Indications for surgery:
  • Size >4 cm
  • Irregular margins
  • Heterogeneous appearance
  • High attenuation (>10 HU) on non-contrast CT
  • Poor contrast washout (<60% at 15 minutes)
  • Hormone production 1

Follow-Up for Non-Surgical Cases

• Benign, non-functioning masses <4 cm: No routine follow-up needed 1
• Indeterminate masses: Annual clinical and biochemical assessment for up to 5 years 5
• Mild autonomous cortisol secretion without surgery: Annual clinical screening for new or worsening comorbidities 1

Important Considerations

• The American Urological Association recommends a multidisciplinary approach involving endocrinologists, surgeons, and radiologists for complex cases 1
• Approximately 20% of adrenal incidentalomas may require surgical intervention 1
• Bilateral adrenal masses require more complex management and may need adrenal vein sampling 1
• Recent evidence suggests that even non-functioning tumors <4 cm may increase metabolic risks, potentially lowering the threshold for surgical intervention 6

Common Pitfalls to Avoid

1. Missing functional tumors: Always perform hormonal evaluation regardless of imaging appearance
2. Inadequate perioperative management: Ensure steroid coverage for cortisol-producing adenomas
3. Unnecessary follow-up: Definitive benign lesions <4 cm don't require continued surveillance
4. Delayed intervention: Growth >5 mm/year warrants consideration for surgery
5. Incomplete evaluation: Hypertensive patients must be screened for aldosteronism