What is the management approach for a left adrenal mass?

Management Approach for a Left Adrenal Mass

The management of a left adrenal mass requires comprehensive hormonal evaluation and appropriate imaging characterization, with surgical intervention recommended for masses >4 cm, those with suspicious imaging features (HU >10, heterogeneity), or any hormone-producing tumors. 1

Initial Diagnostic Evaluation

Imaging Assessment

• Non-contrast CT with Hounsfield Unit (HU) measurement is the cornerstone of initial evaluation:

  • HU <10: Strongly suggests benign lipid-rich adenoma (0% risk of adrenocortical carcinoma) 1
  • HU 10-20: Indeterminate, requires additional evaluation 1
  • HU >20: Higher risk of malignancy, especially if >4 cm or heterogeneous 1

• Additional imaging considerations:

  • Contrast-enhanced CT with washout analysis: >60% washout at 15 minutes suggests benign lesion 1
  • Chemical shift MRI: Alternative when CT contrast is contraindicated or pheochromocytoma suspected 1
  • FDG-PET: For radiologically indeterminate cases 1

Hormonal Evaluation

All patients with adrenal masses require comprehensive hormonal evaluation regardless of symptoms 1, 2:

1. Pheochromocytoma screening (mandatory for all patients):

   • Plasma free metanephrines or 24-hour urinary fractionated metanephrines 1, 2

2. Cortisol screening:

   • 1-mg overnight dexamethasone suppression test (DST)
   • Cutoff ≤50 nmol/L (≤1.8 μg/dL) to exclude cortisol hypersecretion 1, 2
   • Values >138 nmol/L (>5 μg/dL) indicate "autonomous cortisol secretion" 3

3. Aldosterone screening (for hypertensive patients):

   • Aldosterone-to-renin ratio (ARR)
   • ARR >20 ng/dL per ng/mL/hr suggests hyperaldosteronism 1

Management Algorithm

Surgical Indications

Surgery is recommended for 1, 2:

1. Size-based criteria:

   • All masses >6 cm regardless of appearance
   • Masses >4 cm with inhomogeneous appearance or HU >20

2. Functional status:

   • All biochemically confirmed pheochromocytomas
   • Aldosterone-secreting adenomas
   • Cortisol-secreting adenomas
   • Masses with mild autonomous cortisol secretion (MACS) and associated comorbidities (hypertension, diabetes, osteoporosis)

3. Imaging characteristics:

   • Irregular margins or heterogeneous appearance
   • High attenuation (>10 HU) on non-contrast CT
   • Poor contrast washout (<60% at 15 minutes)
   • Growth >5 mm/year on follow-up imaging

Surgical Approach

• Minimally invasive surgery (MIS) is preferred for benign adenomas when feasible 1
• Open adrenalectomy is considered for larger tumors or those with features concerning for malignancy 1

Conservative Management

For masses that appear benign (<10 HU; washout >50%), small (<4 cm), and non-functioning:

• No further imaging follow-up is needed if clearly benign (HU ≤10) and <4 cm 1, 2
• For more indeterminate lesions, repeat evaluation for growth after 3-12 months 4

Follow-up Recommendations

Imaging Follow-up

• Benign-appearing adenomas <4 cm: No further follow-up imaging if clearly benign (HU ≤10) 1, 2
• Benign-appearing adenomas ≥4 cm: Repeat imaging in 6-12 months 1
• Indeterminate lesions: Repeat evaluation after 3-12 months 4

Hormonal Follow-up

• For non-operated patients with non-functioning masses:
  • Consider repeat screening for pheochromocytoma and hypercortisolism at 1-2 years 1, 4
  • Particularly important for patients with MACS who did not undergo surgery 2

Important Considerations and Pitfalls

• Pitfall #1: Failing to perform hormonal evaluation on all adrenal masses, even those that appear benign on imaging. Up to 12-23% of incidentalomas may demonstrate subclinical hormone production 1.

• Pitfall #2: Relying solely on size criteria for surgical decision-making. While size is important, imaging characteristics (HU values, heterogeneity) and hormonal status are equally crucial 1, 2.

• Pitfall #3: Missing mild autonomous cortisol secretion (MACS), which can increase risk of morbidity and mortality even without overt Cushing's syndrome 2.

• Pitfall #4: Overlooking the need to screen and treat potential cortisol-related comorbidities (hypertension, diabetes, osteoporosis) in patients with MACS 2, 3.