What is the recommended workup for an adrenal tumor?

Comprehensive Workup for Adrenal Tumors

The recommended workup for an adrenal tumor must include a focused history and physical examination, appropriate imaging studies, and comprehensive hormonal evaluation to determine malignancy risk and functional status. 1

Initial Evaluation

History and Physical Examination

• Specific symptoms to assess:
  • Hypertension (especially resistant or paroxysmal)
  • Hypokalemia
  • Unexplained weight gain/loss
  • Hirsutism or virilization in women
  • Gynecomastia in men
  • Muscle weakness
  • Easy bruising
  • Facial plethora
  • Headaches, palpitations, sweating episodes
  • History of malignancy

Imaging Studies

1. First-line imaging: Non-contrast CT scan 1

   • Homogeneous lesions with Hounsfield Units (HU) ≤10 are considered benign
   • Lesions with HU >10 require further evaluation

2. Second-line imaging (for indeterminate masses): 1

   • Washout CT protocol OR
   • Chemical-shift MRI

3. Additional imaging considerations:

   • FDG-PET/CT may be useful for suspected malignancy or metastatic disease 1
   • Adrenal biopsy is generally NOT recommended for routine workup 1

Hormonal Evaluation

1. Cortisol Secretion (Required for ALL patients) 1, 2

• 1mg overnight dexamethasone suppression test
  • Cortisol cutoff ≤50 nmol/L (≤1.8 μg/dL) indicates normal suppression
  • Values >50 nmol/L suggest autonomous cortisol secretion

2. Catecholamine Secretion 1

• When to test:

  • All patients with adrenal mass >10 HU on non-contrast CT
  • Any patient with symptoms of catecholamine excess
  • Not required in patients with unequivocal adrenocortical adenomas (HU <10) without symptoms

• Preferred tests:

  • Plasma free metanephrines OR
  • 24-hour urinary fractionated metanephrines

3. Aldosterone Secretion 1

• When to test:

  • Patients with hypertension
  • Patients with hypokalemia

• Test: Aldosterone-to-renin ratio

4. Sex Hormone Evaluation 1

• When to test:
  • Suspected adrenocortical carcinoma
  • Clinical signs of virilization/feminization

Risk Stratification for Malignancy

High-risk features requiring surgical consideration:

• Size >4 cm
• Inhomogeneous appearance
• HU >20 on non-contrast CT
• Irregular margins
• Growth rate >5 mm/year
• Local invasion
• Evidence of hormone hypersecretion

Management Algorithm

1. Benign, non-functional adenomas <4 cm with HU <10:

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

2. Non-functional lesions that are radiologically benign but ≥4 cm:

   • Repeat imaging in 6-12 months 1

3. Indeterminate non-functional adrenal lesions:

   • Repeat imaging in 3-6 months OR
   • Consider surgical resection based on risk factors 1

4. Functional tumors:

   • Cortisol-secreting masses with overt Cushing's syndrome: Adrenalectomy 1
   • Aldosterone-secreting masses: Adrenalectomy 1
   • Pheochromocytomas: Adrenalectomy after appropriate alpha-blockade 1

5. Suspected malignancy:

   • Multidisciplinary discussion
   • Surgical resection (minimally invasive if <6 cm and no local invasion; open approach for larger or invasive tumors) 1

Important Caveats

• Multidisciplinary approach: Involve endocrinologists, surgeons, and radiologists when imaging is not consistent with benign lesion, there is hormone hypersecretion, significant growth, or when considering surgery 1

• Adrenal vein sampling: Required before adrenalectomy in primary aldosteronism to confirm lateralization 1

• Mild autonomous cortisol secretion (MACS): Even subclinical cortisol excess is associated with increased cardiovascular morbidity and metabolic abnormalities 2, 3

• Pitfall to avoid: Never perform interventional procedures (biopsy, surgery) on suspected pheochromocytoma without appropriate alpha-blockade due to risk of hypertensive crisis 1

• Growth monitoring: Adrenalectomy should be considered for tumors growing >5 mm/year after repeating functional workup 1