What is the management plan for an adrenal mass?

Management of Adrenal Masses

Adrenal masses require a systematic approach including comprehensive hormonal evaluation and dedicated imaging, with surgical intervention recommended for masses >4 cm with inhomogeneous appearance or HU >20, all masses >6 cm regardless of appearance, and all hormonally active tumors. 1

Diagnostic Evaluation

Hormonal Assessment

All patients with adrenal masses should undergo:

1. Cortisol screening:

   • 1-mg overnight dexamethasone suppression test (DST)
   • Cortisol cutoff ≤50 nmol/L (≤1.8 μg/dL) to exclude hypersecretion
   • Values >50 nmol/L indicate "mild autonomous cortisol secretion" (MACS) 1, 2

2. Catecholamine screening:

   • Plasma free metanephrines or 24-hour urinary fractionated metanephrines
   • Values >2× upper limit of normal strongly suggest pheochromocytoma 1
   • Critical before any surgical intervention to avoid hypertensive crisis

3. Aldosterone screening (especially in hypertensive patients):

   • Aldosterone-to-renin ratio (ARR)
   • ARR >20 ng/dL per ng/mL/hr has >90% sensitivity/specificity for hyperaldosteronism 1

4. Androgen evaluation when indicated:

   • DHEAS and testosterone measurements 1

Imaging Evaluation

1. Non-contrast CT:

   • Primary imaging modality for characterization
   • Hounsfield Units (HU) assessment:
     • HU ≤10: Benign adenoma (0% risk of adrenocortical carcinoma)
     • HU >10: Requires further evaluation 1, 3

2. Contrast-enhanced CT:

   • Washout calculation:

     • 60% washout at 15 minutes suggests benign lesion

     • <60% washout raises concern for malignancy 1, 3

3. Chemical shift MRI:

   • Alternative when CT contrast is contraindicated
   • Signal intensity loss in opposed-phase images indicates benign adenoma 1

4. FDG-PET:

   • For radiologically indeterminate cases
   • High tracer uptake suggests malignancy 1

Management Algorithm

Surgical Intervention Indicated For:

1. Size-based criteria:

   • All masses >6 cm regardless of appearance
   • Masses >4 cm with inhomogeneous appearance or HU >20 1, 2

2. Imaging characteristics:

   • Irregular margins
   • Heterogeneous appearance
   • Poor contrast washout (<60% at 15 minutes)
   • Growth >5 mm/year on follow-up imaging 1

3. Hormonal status:

   • All biochemically confirmed pheochromocytomas
   • Aldosterone-secreting adenomas
   • Cortisol-secreting adenomas
   • Patients with MACS and relevant comorbidities (individualized approach) 1, 2

Surgical Approach:

• Minimally invasive surgery (MIS): Preferred for benign adenomas when feasible
• Open adrenalectomy: For larger tumors or those with features concerning for malignancy 1
• Perioperative management: Steroid coverage mandatory for cortisol-producing adenomas to prevent adrenal crisis 1

Conservative Management:

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

   • No further follow-up imaging or functional testing required 1, 2, 4

2. Benign-appearing adenomas ≥4 cm:

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

3. Non-operated patients with non-functioning masses:

   • Consider repeat screening for pheochromocytoma and hypercortisolism at 1-2 years 1, 4

Common Pitfalls and Caveats

1. Never skip hormonal evaluation even for apparently non-functioning masses, as subclinical hormone production can have significant health implications 1, 2

2. Pheochromocytoma screening is essential before any invasive procedure to avoid potentially fatal hypertensive crisis 1

3. Mild autonomous cortisol secretion (MACS) requires careful evaluation of comorbidities (hypertension, diabetes, osteoporosis) that might benefit from surgical intervention 2

4. Washout characteristics on CT are more reliable than size alone for determining malignancy risk 1, 3

5. Adrenal biopsy is rarely indicated and should be avoided if pheochromocytoma has not been excluded 5

6. Benign-appearing lesions that remain unchanged on follow-up imaging do not require continued surveillance 1