What is the management approach for adrenal adenoma?

Management of Adrenal Adenoma

Adrenal adenomas require a systematic approach based on radiological characteristics and hormonal functionality, with surgical intervention indicated for tumors >4 cm with suspicious features, hormone-secreting tumors, or those showing significant growth during follow-up. 1

Diagnostic Evaluation

Radiological Assessment

• Non-contrast CT is the first-line imaging modality:

  • Hounsfield Units (HU) ≤10 indicates benign adenoma (0% risk of adrenocortical carcinoma) 1
  • Homogeneous lesions with HU ≤10 are benign and require no additional imaging regardless of size 2
  • Lesions with HU >10 require further evaluation

• Additional imaging characteristics suggesting malignancy:

  • Size >4 cm
  • Irregular morphology
  • Heterogeneous appearance
  • Poor contrast washout (<60% at 15 minutes)
  • Evidence of invasion or necrosis 3, 1

Hormonal Evaluation

All patients with adrenal adenomas require comprehensive hormonal assessment:

1. Cortisol assessment: 1mg overnight dexamethasone suppression test

   • Cortisol ≤50 nmol/L (≤1.8 μg/dL): Normal
   • Cortisol 51-138 nmol/L (1.9-5.0 μg/dL): Possible autonomous cortisol secretion
   • Cortisol >138 nmol/L (>5.0 μg/dL): Autonomous cortisol secretion 3, 1, 2

2. Catecholamine assessment: Plasma free metanephrines or 24-hour urinary fractionated metanephrines

   • Values >2× upper limit of normal suggest pheochromocytoma 1

3. Aldosterone assessment (in patients with hypertension/hypokalemia): Aldosterone-to-renin ratio (ARR)

   • ARR >20 ng/dL per ng/mL/hr has >90% sensitivity/specificity for hyperaldosteronism 1

Management Approach

Surgical Management

Surgery is indicated for:

1. Size criteria:

   • Tumors >4 cm without characteristic benign imaging features 1, 2
   • Smaller tumors with suspicious radiological features 3

2. Hormonal functionality:

   • All pheochromocytomas (with preoperative alpha-blockade for 1-3 weeks) 3, 1
   • Aldosterone-producing adenomas (if unilateral) 1
   • Cortisol-producing adenomas causing overt Cushing's syndrome 1
   • Consider surgery for mild autonomous cortisol secretion (MACS) with progressive metabolic comorbidities (hypertension, diabetes, osteoporosis) 3, 1, 2

3. Surgical approach:

   • Laparoscopic/robotic adrenalectomy for smaller (<5 cm), contained masses 3, 1
   • Open adrenalectomy for larger (>5 cm) tumors or those with features concerning for malignancy 3

Non-surgical Management

For non-functional, radiologically benign adenomas:

1. Benign-appearing adenomas <4 cm with HU ≤10:

   • No further follow-up imaging or functional testing required 1

2. Benign-appearing adenomas ≥4 cm:

   • Repeat imaging in 6-12 months
   • Consider surgery if growth >5 mm/year 1

3. Indeterminate lesions:

   • Repeat imaging in 3-12 months 1
   • Consider surgery if growth >8 mm over 3-12 months 4

4. Medical therapy (when surgery is contraindicated):

   • For cortisol excess: Ketoconazole, metyrapone, or mifepristone
   • For aldosterone excess: Mineralocorticoid receptor antagonists 1

Special Considerations

Bilateral Adrenal Adenomas

• Work up and treat each mass individually 3
• Avoid bilateral adrenalectomy for asymptomatic cortisol-secreting adenomas 3
• Consider partial adrenalectomy in select cases (e.g., bilateral pheochromocytomas) 3
• Collect 17-hydroxyprogesterone levels to rule out congenital adrenal hyperplasia 3

High-Risk Populations

• Urgent assessment for pregnant women, children, and people younger than 40 years due to greater risk of adrenal malignancy 3
• MRI is preferred over CT in these populations 3
• Consider quality of life and medical comorbidities in management decisions for elderly patients 3

Follow-up Recommendations

• Non-operated patients with non-functioning masses:

  • Consider repeat screening for pheochromocytoma and hypercortisolism at 1-2 years 1

• Patients with MACS:

  • Regular monitoring and management of cortisol-related comorbidities (hypertension, diabetes, osteoporosis) 1, 2

• Post-surgical follow-up:

  • Lifelong surveillance for malignant pheochromocytoma
  • Regular monitoring for recurrence in Cushing's syndrome and pheochromocytoma 1

Common Pitfalls to Avoid

1. Failing to exclude pheochromocytoma before surgery, which can lead to life-threatening hypertensive crisis
2. Overlooking mild autonomous cortisol secretion, which is associated with increased cardiovascular morbidity and mortality 1, 2
3. Using minimally invasive approaches for suspected adrenocortical carcinoma, which can lead to higher recurrence rates 3
4. Performing unnecessary biopsies, which have limited clinical value and should not be part of initial workup 3
5. Missing congenital adrenal hyperplasia in patients with bilateral adrenal masses 3