What is the initial approach to managing an adrenal adenoma?

Initial Approach to Managing an Adrenal Adenoma

The initial approach to managing an adrenal adenoma requires comprehensive radiological assessment and hormonal evaluation to determine malignancy risk and functional status, followed by appropriate treatment decisions based on these findings. 1, 2

Diagnostic Evaluation

Radiological Assessment

• First-line imaging should be non-contrast CT to determine if the mass is benign or malignant 2
• Benign features include:
  • Homogeneous, well-circumscribed appearance
  • Hounsfield units (HU) ≤10 on unenhanced CT 2
  • Size <4 cm 1
• For indeterminate masses on non-contrast CT, proceed with second-line imaging: washout CT or chemical-shift MRI 2
• Masses >4 cm with inhomogeneous appearance or >20 HU should be considered suspicious for malignancy 2

Hormonal Evaluation

• All patients with adrenal incidentalomas should undergo:
  • 1 mg overnight dexamethasone suppression test (DST) to screen for autonomous cortisol secretion 2
  • Serum cortisol ≤50 nmol/L (≤1.8 μg/dL) excludes cortisol hypersecretion 2
  • Serum cortisol between 51-138 nmol/L (1.9-5.0 μg/dL) suggests possible autonomous cortisol secretion 2
  • Serum cortisol >138 nmol/L (>5.0 μg/dL) indicates autonomous cortisol secretion 1
• For patients with hypertension and/or hypokalemia:
  • Measure aldosterone/renin ratio to screen for primary aldosteronism 2
  • A ratio >20 ng/dL per ng/mL/hr suggests hyperaldosteronism 2
• For patients with adrenal masses ≥10 HU on non-contrast CT or with symptoms of catecholamine excess:
  • Test for pheochromocytoma using plasma free metanephrines or 24-hour urinary metanephrines and normetanephrines 2, 3
• For patients with suspected adrenocortical carcinoma or virilization:
  • Perform serum androgen testing, including DHEAS and testosterone 2

Management Algorithm

Non-functioning Adenomas with Benign Features

• For benign non-functional adenomas <4 cm, myelolipomas, and other small masses containing macroscopic fat:
  • No further follow-up imaging or functional testing is required 1, 2
• For radiologically benign (<10 HU) but ≥4 cm non-functional lesions:
  • Repeat imaging in 6-12 months 1
  • If growth is <3 mm/year, no further imaging or functional testing is required 1
  • If growth is 3-5 mm/year, continued surveillance may be appropriate 2
  • If growth is >5 mm/year, repeat functional work-up and consider surgical intervention 1, 2

Functioning Adenomas

• For cortisol-secreting adenomas:
  • With overt Cushing's syndrome: surgical intervention 2
  • With mild autonomous cortisol secretion and related comorbidities (hypertension, diabetes, osteoporosis): consider adrenalectomy based on individualized approach 1
• For aldosterone-secreting adenomas:
  • Surgical intervention is recommended 1
  • Confirm diagnosis with saline challenge test and consider adrenal vein sampling to lateralize production 1
• For pheochromocytomas:
  • Surgical intervention is recommended 1
  • Appropriate preoperative alpha-blockade is essential 3

Indeterminate Non-functioning Lesions

• Management options include:
  • Repeat imaging in 3-6 months 1
  • Surgical resection if concerning features persist 1
• All patients with adrenal incidentalomas growing >5 mm/year should undergo repeat functional work-up before considering surgery 1

Surgical Considerations

• Minimally invasive surgery (MIS) should be performed when feasible for benign-appearing functional tumors 1
• Open adrenalectomy should be considered for:
  • Masses with suspicious imaging features suggesting malignancy 1
  • Larger masses (>6 cm) 1

Special Considerations

• For bilateral adrenal incidentalomas:
  • Each lesion should be separately characterized following the same protocol as unilateral masses 1
  • Consider measuring serum 17-hydroxyprogesterone to exclude congenital adrenal hyperplasia 2
• Adrenal mass biopsy should not be performed routinely 2
  • Only consider when diagnosis of metastatic disease from an extra-adrenal malignancy would alter management 2

Common Pitfalls to Avoid

• Failing to perform appropriate hormonal testing even in asymptomatic patients 2
• Overlooking mild autonomous cortisol secretion, which can contribute to metabolic comorbidities 4
• Unnecessary follow-up imaging for clearly benign, non-functional adenomas <4 cm 1
• Not considering a multidisciplinary approach for complex cases 2