What is the initial management for a left adrenal gland lesion?

Initial Management of Left Adrenal Gland Lesion

All patients with a newly discovered left adrenal gland lesion require both imaging characterization and hormonal evaluation as the initial management approach. 1, 2

Step 1: Obtain Unenhanced CT (If Not Already Done)

• If the lesion was discovered on contrast-enhanced imaging, obtain a dedicated unenhanced CT to measure attenuation in Hounsfield Units (HU) 1
• Measure the lesion's maximum diameter and assess for homogeneity, well-defined margins, and any features suggesting malignancy (heterogeneity, invasion, necrosis) 1

Step 2: Perform Initial Hormonal Screening

All adrenal incidentalomas require hormonal evaluation regardless of imaging appearance, as approximately 5% harbor subclinical hormone production requiring treatment. 2, 3

Required Tests:

• 1 mg overnight dexamethasone suppression test for autonomous cortisol secretion in all patients 4
• Plasma metanephrines or 24-hour urinary fractionated metanephrines to exclude pheochromocytoma (must be done before any biopsy to prevent potentially fatal catecholamine crisis) 1
• Plasma aldosterone-to-renin ratio if the patient has hypertension and/or hypokalemia 4

Step 3: Risk Stratification Based on Imaging

Benign Lesion (<10 HU, <4 cm, homogeneous):

• No further imaging or hormonal follow-up required if initial hormonal screening is normal 1, 2, 3
• This applies to benign non-functional adenomas, myelolipomas, and other small masses containing macroscopic fat 1, 2

Benign-Appearing but ≥4 cm:

• Repeat imaging in 6-12 months even if radiologically benign, as most pheochromocytomas and adrenocortical carcinomas were >4 cm at diagnosis 1, 2, 3
• On subsequent imaging, growth <3 mm/year requires no further follow-up 1, 2, 4
• Growth >5 mm/year warrants adrenalectomy after repeating functional workup 1, 2, 4

Indeterminate Lesion (>10 HU on unenhanced CT):

• Obtain second-line imaging: either delayed contrast-enhanced CT with washout protocol or chemical shift MRI 1
• If still indeterminate after second-line imaging, consider repeat imaging in 3-6 months versus surgical resection through shared decision-making 1

Obviously Malignant Features:

• Large size (>4 cm), heterogeneity, invasion, or necrosis warrant immediate surgical referral if the patient is a surgical candidate 1
• For suspected adrenocortical carcinoma, strongly recommend open adrenalectomy for masses >5 cm due to risk of peritoneal dissemination with minimally invasive approaches 1

Step 4: Special Considerations for Left Adrenal Lesions

In patients with known extra-adrenal malignancy and a left adrenal mass suspicious for metastasis, EUS-guided fine needle aspiration (EUS-FNA) via transgastric approach is recommended for tissue diagnosis. 1

• The left adrenal gland is accessible via transgastric EUS-FNA, which can be performed during the same session as mediastinal staging 1
• Metastatic risk to the adrenal gland ranges from 25-72% depending on the primary tumor in patients with known malignancy 2, 3
• EUS-FNA has higher accuracy than percutaneous biopsy with fewer complications 1

Critical Pitfalls to Avoid

• Never perform adrenal biopsy without first excluding pheochromocytoma, as several deaths have been reported from biopsying unsuspected pheochromocytomas 1
• Do not skip hormonal evaluation even for radiologically benign-appearing lesions, as subclinical hormone excess occurs in 5% of incidentalomas 2, 3
• Avoid routine biopsy for adrenal incidentalomas; it is rarely indicated and carries risks including tumor seeding, hemorrhage, and pneumothorax 1, 3
• Do not apply the <4 cm "no follow-up" rule to patients with known extra-adrenal malignancy, young adults, children, or pregnant patients, as these populations have higher malignancy risk 1, 2, 3