What are the management and treatment options for a patient with a left adrenal mass?

Management of Left Adrenal Mass

All patients with a left adrenal mass require both hormonal evaluation to exclude functional tumors and imaging characterization to assess malignancy risk, with management decisions based on size, imaging characteristics, and functional status. 1

Initial Diagnostic Workup

Mandatory Hormonal Screening

Every patient requires the following tests, regardless of how benign the mass appears on imaging:

• 1 mg overnight dexamethasone suppression test to screen for autonomous cortisol secretion (administer 1 mg dexamethasone at 11 PM, measure serum cortisol at 8 AM) 2, 3
• Plasma free metanephrines or 24-hour urinary metanephrines to exclude pheochromocytoma 2, 3
• Aldosterone-to-renin ratio only if the patient has hypertension and/or hypokalemia 2, 3

This comprehensive hormonal screening is essential because approximately 5% of radiologically benign-appearing incidentalomas harbor subclinical hormone production requiring treatment. 2

Imaging Characterization Algorithm

First-line imaging: Unenhanced CT to measure Hounsfield units (HU) 2

• If HU ≤10: The mass is definitively a benign lipid-rich adenoma 2
• If HU >10: Proceed to second-line imaging with either washout CT or chemical shift MRI 1, 2

Critical imaging caveat: Approximately one-third of pheochromocytomas may washout in the characteristic range of an adenoma, and conversely, one-third of adrenal adenomas do not washout in the adenoma range. Malignant masses can also demonstrate adenoma-range washout. 1

Management Based on Functional Status

Functional Masses (Surgical Indications)

Adrenalectomy is mandatory for: 1, 3

• Pheochromocytomas (minimally invasive surgery when feasible)
• Aldosterone-secreting adenomas causing primary aldosteronism (minimally invasive surgery when feasible)
• Cortisol-secreting adenomas with clinically apparent Cushing's syndrome

For mild autonomous cortisol secretion (MACS): Consider adrenalectomy only in younger patients with progressive metabolic comorbidities attributable to cortisol excess after shared decision-making. 2

Non-Functional Masses: Size-Based Algorithm

Small masses (<4 cm) with benign imaging (HU ≤10):

• No further follow-up imaging or functional testing required 1, 2, 4
• This applies to benign non-functional adenomas, myelolipomas, and other small masses containing macroscopic fat 1, 4
• The risk of malignant transformation is 0% to <1% 2

Larger masses (≥4 cm) with benign imaging (HU <10):

• Repeat imaging in 6-12 months 1, 4
• This recommendation exists because most surgically resected pheochromocytomas and adrenocortical carcinomas were >4 cm at diagnosis 4

Indeterminate masses (despite second-line imaging):

• Use shared decision-making between patient and clinician 1
• Management options: repeat imaging in 3-6 months versus surgical resection 1

Growth-Based Follow-Up Criteria

If surveillance imaging is performed:

• Growth <3 mm/year: No further imaging or functional testing required 1, 4
• Growth >5 mm/year: Adrenalectomy should be considered after repeating functional work-up 1, 4

Surgical Approach Selection

Minimally invasive adrenalectomy can be offered for suspected adrenocortical carcinomas that can be safely resected without rupturing the tumor capsule. 1

Open adrenalectomy should be considered for larger adrenocortical carcinomas or those with locally advanced features, lymph node metastases, or tumor thrombus in the renal vein/inferior vena cava. 1

Special Population Considerations

Young adults, children, and pregnant patients: Adrenal lesions are more likely malignant in these populations, requiring expedited evaluation. Low-dose CT or chemical shift MRI should be preferred to minimize radiation exposure. 1, 4

Patients with history of extra-adrenal malignancy: The rate of metastatic disease to the adrenal gland ranges from 25-72% depending on primary tumor type, requiring closer evaluation even for smaller lesions. 2, 4

Bilateral adrenal masses: Each lesion should be separately characterized using the same protocol as unilateral masses. Additionally, measure serum 17-hydroxyprogesterone to exclude congenital adrenal hyperplasia and assess for adrenal insufficiency in suspected cases of bilateral infiltrative disease, metastases, or hemorrhage. 1, 3

Critical Pitfalls to Avoid

• Never skip initial hormonal evaluation even if the mass appears benign on imaging, as functional abnormalities occur in approximately 5% of cases 2, 4
• Adrenal mass biopsy should NOT be performed routinely for workup of adrenal incidentalomas—it is rarely indicated and carries risks including potential tumor seeding 1, 2, 4
• Always exclude pheochromocytoma before any biopsy if one is being considered 1
• Avoid unnecessary repeated imaging for small adrenal masses with benign characteristics, as this leads to increased radiation exposure, patient anxiety, and healthcare costs 2