What is the management plan for an adrenal mass?

Management of Adrenal Masses

Adrenal masses require a systematic approach including hormonal evaluation and imaging studies, with surgical intervention indicated for masses >4 cm, those with concerning radiological features (HU >20, inhomogeneous), or any hormone-producing tumors. 1

Initial Evaluation

Imaging Assessment

1. Dedicated adrenal imaging is essential for all adrenal masses 1, 2
   • Non-contrast CT is the first-line imaging modality
     • HU ≤10: Benign adenoma (0% risk of adrenocortical carcinoma)
     • HU >20: Increased suspicion for malignancy
   • For indeterminate lesions, proceed with:
     • Contrast-enhanced CT washout study (>60% washout at 15 minutes suggests benign lesion)
     • Chemical shift MRI (particularly useful when CT contrast is contraindicated)
   • FDG-PET for radiologically indeterminate cases with suspicion of malignancy

Hormonal Evaluation

All patients with adrenal masses ≥1 cm should undergo complete hormonal evaluation 1, 2:

1. Mandatory tests for all patients:

   • 1-mg overnight dexamethasone suppression test (cortisol ≤50 nmol/L or ≤1.8 µg/dL is normal)
   • Plasma-free or 24-hour urinary fractionated metanephrines (pheochromocytoma screening)

2. Additional tests:

   • Aldosterone-to-renin ratio (especially in hypertensive patients)
   • Electrolyte panel (to screen for hypokalemia in primary aldosteronism)

Management Algorithm

Surgical Management

Surgery is indicated for 1, 2:

• Masses >4 cm in diameter
• Masses with irregular margins or heterogeneous appearance
• High attenuation (>10 HU) on non-contrast CT
• Poor contrast washout (<60% at 15 minutes)
• Any hormone-producing tumor
• Growth >5 mm/year on follow-up imaging

Surgical Approach

• Minimally invasive surgery (MIS) is preferred for benign adenomas
• Open adrenalectomy should be considered for:
  • Larger tumors
  • Features concerning for malignancy

Non-Surgical Management

For benign-appearing adrenal adenomas 1, 2:

• <4 cm with HU ≤10: No further follow-up imaging or functional testing required
• ≥4 cm: Repeat imaging in 6-12 months
• Growth <3 mm/year: No further imaging or functional testing required
• Growth >5 mm/year: Repeat functional work-up and consider adrenalectomy

Special Considerations

Mild Autonomous Cortisol Secretion (MACS)

• Defined as cortisol >50 nmol/L (>1.8 µg/dL) after dexamethasone suppression test without overt Cushing's syndrome 2
• Screen for potential cortisol-related comorbidities (hypertension, type 2 diabetes)
• Consider surgical treatment in patients with relevant comorbidities 2

Perioperative Management

• Perioperative steroid coverage is mandatory for patients with cortisol-producing adenomas 1
• Gradual tapering of glucocorticoid replacement therapy with follow-up cortisol testing

Common Pitfalls and Caveats

1. Always exclude pheochromocytoma before any adrenal biopsy 1

   • 1.5-14% of incidentally discovered adrenal masses are pheochromocytomas
   • Failure to identify can lead to life-threatening hypertensive crisis during procedures

2. Correlation of imaging with biochemical testing is crucial 1

   • Radiologically benign-appearing masses can still be hormonally active

3. Adrenal biopsy is rarely required 3

   • Modern imaging techniques can characterize most adrenal masses
   • Biopsy should be considered only after excluding pheochromocytoma and when diagnosis remains uncertain after comprehensive imaging

4. Size is not the only criterion for surgery

   • Even smaller masses with concerning radiological features or hormonal activity require surgical management

The evidence strongly supports a systematic approach to adrenal masses, with the most recent guidelines emphasizing the importance of both imaging characteristics and hormonal evaluation in determining management strategy 1, 2.