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 comprehensive hormonal evaluation regardless of how benign the mass appears on imaging, as approximately 5% of radiologically benign incidentalomas have subclinical hormone production requiring treatment 2:

• Perform 1 mg overnight dexamethasone suppression test (give 1 mg at 11 PM, measure serum cortisol at 8 AM) to screen for autonomous cortisol secretion in all patients 1, 3
• Measure plasma free metanephrines or 24-hour urinary metanephrines/normetanephrines to exclude pheochromocytoma before any intervention 1, 2, 3
• Check aldosterone-to-renin ratio only if the patient has hypertension and/or hypokalemia 2, 3

Imaging Characterization Algorithm

First-line imaging: Non-contrast CT to measure Hounsfield units (HU) 1, 2:

• If HU ≤10: Definitively benign lipid-rich adenoma—proceed to size-based management 1, 2
• If HU >10: Indeterminate—requires second-line imaging with either washout CT or chemical shift MRI 1, 2

Important caveat: Approximately one-third of pheochromocytomas may washout in the characteristic range of an adenoma on washout CT, and one-third of benign adenomas do not washout in the adenoma range, so clinicians must be aware of these limitations 1

Management Algorithm Based on Functional Status and Size

Functional Masses (Regardless of Size)

Adrenalectomy is indicated for 1, 3:

• Pheochromocytomas (mandatory surgical removal)
• Aldosterone-secreting adenomas causing primary aldosteronism
• Cortisol-secreting masses with clinically apparent Cushing's syndrome
• Use minimally invasive surgery when feasible for these procedures 1

For mild autonomous cortisol secretion (MACS), adrenalectomy should be considered only in younger patients with progressive metabolic comorbidities attributable to cortisol excess after shared decision-making 2

Non-Functional Masses: Size-Based Management

Small masses (<4 cm) with benign imaging (HU ≤10) 1, 2, 4:

• No further follow-up imaging or functional testing required—this includes benign non-functional adenomas, myelolipomas, and other small masses containing macroscopic fat
• Risk of malignant transformation is 0% to <1% 2

Larger masses (≥4 cm) with benign imaging (HU <10) 1, 4:

• Repeat imaging in 6-12 months due to higher malignancy risk
• Most surgically resected pheochromocytomas and adrenocortical carcinomas were >4 cm at diagnosis 4

Indeterminate non-functional masses (after second-line imaging) 1:

• Use shared decision-making between patient and clinician
• Options: Repeat imaging in 3-6 months versus surgical resection
• There are no strong data to guide the best approach in this scenario 1

Growth Rate Thresholds During Surveillance

If follow-up imaging is performed 1, 4:

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

Special Populations Requiring Expedited Evaluation

Young adults, children, and pregnant patients 1:

• Adrenal lesions are more likely to be malignant in these populations
• Evaluation should be expedited
• Consider low-dose CT or chemical shift MRI as first-line imaging to minimize radiation exposure 1

Patients with history of extra-adrenal malignancy 2, 4:

• Metastatic disease to the adrenal gland occurs in 25-72% depending on primary tumor type 2, 4
• Requires closer evaluation even for smaller lesions
• Adrenal biopsy may be considered when diagnosis of metastatic disease would change management, but only after pheochromocytoma has been excluded 1, 5

Critical Pitfalls to Avoid

Never perform adrenal biopsy routinely 1, 2, 4:

• Biopsy is rarely indicated for adrenal incidentalomas
• Risk of tumor seeding in suspected adrenocortical carcinoma
• Only consider when diagnosis of metastatic disease from extra-adrenal malignancy would be of value, and only after excluding pheochromocytoma 1

Do not skip initial hormonal evaluation 2:

• Even radiologically benign-appearing lesions require hormonal screening
• Approximately 5% harbor subclinical hormone production requiring treatment 2

Avoid unnecessary repeated imaging 2:

• For small (<4 cm) benign-appearing masses with HU ≤10, no surveillance is needed
• Leads to increased radiation exposure, patient anxiety, and healthcare costs 2

Surgical Considerations

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 tumors, lymph node metastases, or tumor thrombus in the renal vein/inferior vena cava 1