What is the management plan for an adrenal mass?

Management of Adrenal Masses

The management of adrenal masses requires a systematic approach including dedicated adrenal imaging, comprehensive hormonal evaluation, and risk stratification to determine the need for surgery or surveillance. 1, 2

Initial Evaluation

Imaging Assessment

• Non-contrast CT is the first-line imaging modality:
  • Homogeneous lesions with Hounsfield units (HU) ≤10 are benign and require no additional imaging regardless of size 2, 3
  • Lesions with HU >10 require further evaluation with contrast-enhanced CT to assess washout characteristics

  • 60% washout at 15 minutes suggests benign lesion 2

Hormonal Evaluation

All patients with adrenal masses should undergo complete hormonal assessment:

1. Cortisol Assessment:

   • 1mg overnight dexamethasone suppression test (DST)
   • Interpretation: <50 nmol/L excludes autonomous cortisol secretion; 51-138 nmol/L suggests possible autonomous cortisol secretion; >138 nmol/L indicates autonomous cortisol secretion 2

2. Catecholamine Assessment:

   • Plasma free metanephrines or 24-hour urinary metanephrines
   • Particularly important for nodules with HU >10 on non-contrast CT
   • Values >2× upper limit of normal are diagnostic for pheochromocytoma 2

3. Aldosterone Assessment:

   • Aldosterone-to-renin ratio for patients with hypertension and/or hypokalemia
   • Ratio >20 ng/dL per ng/mL/hr has >90% sensitivity/specificity for hyperaldosteronism 2

Management Decision Algorithm

Surgical Management Indications

Surgery is recommended for:

1. Size-based criteria:

   • Adrenal masses >4 cm that are inhomogeneous or have HU >20 due to high risk of malignancy 3

2. Hormone-producing tumors:

   • Pheochromocytoma: Adrenalectomy with preoperative alpha-blocker treatment 2
   • Aldosterone-secreting adenoma: Adrenalectomy (consider adrenal vein sampling prior to surgery) 2
   • Cortisol-secreting adenoma: Adrenalectomy, especially with clinically apparent Cushing's syndrome or progressive metabolic comorbidities 2

3. Imaging characteristics concerning for malignancy:

   • Heterogeneous appearance
   • Irregular margins
   • Local invasion
   • Size >4 cm

Conservative Management

For non-functional, benign-appearing masses:

• Asymptomatic, non-functioning unilateral adrenal masses with obvious benign features on imaging (HU <10, homogeneous) do not require surgery 3
• Small myelolipomas (<4 cm) can be managed conservatively 2

Follow-up Protocol

For Non-operated Masses

• Benign-appearing lesions (<10 HU; washout >50%), small (<3 cm), and non-functioning:

  • Repeat imaging in 6-12 months 2, 4
  • No further follow-up needed if stable and <4 cm 2

• Indeterminate lesions:

  • Repeat evaluation for growth after 3-12 months 4
  • Consider surgery if growth >5 mm/year is observed 2

• Mild Autonomous Cortisol Secretion (MACS):

  • Screen for potential cortisol-related comorbidities (hypertension, type 2 diabetes)
  • Ensure appropriate treatment of these comorbidities 3
  • Consider individualized surgical approach based on comorbidity severity 3

Special Considerations

Preoperative Preparation

• For suspected pheochromocytoma: Preoperative alpha-blockade is essential to prevent dangerous intraoperative hypertensive crisis 2
• For cortisol-producing tumors: Perioperative steroid coverage is required 2

Multidisciplinary Approach

• Management requires collaboration between radiologists, endocrinologists, surgeons, and anesthesiologists 2
• Multidisciplinary review is recommended when:
  • Imaging is not consistent with a benign lesion
  • There is evidence of hormone hypersecretion 2

Common Pitfalls to Avoid

1. Skipping hormonal evaluation based on benign imaging appearance - Even classic-appearing myelolipomas can be hormonally active 2

2. Overlooking subclinical hormone production - Mild autonomous cortisol secretion can contribute to metabolic comorbidities without overt Cushing's syndrome 2

3. Inadequate preoperative preparation - Undiagnosed pheochromocytoma can lead to dangerous intraoperative hypertensive crisis 2

4. Unnecessary surgery for small, benign, non-functioning lesions with clear benign characteristics on imaging 3