Management of Benign Adrenal Adenoma

Growth Rate Assessment

• For a benign adrenal adenoma with a growth rate of <5 mm/year, the American Urological Association recommends repeat imaging in 6-12 months, as this growth rate does not meet the threshold for surgical intervention 1
• The National Comprehensive Cancer Network suggests that growth between 3-5 mm/year warrants continued surveillance with repeat imaging in 6-12 months 1, 2

Size Considerations

• The American College of Radiology states that benign-appearing adenomas <4 cm with confirmed benign imaging characteristics require no further follow-up if they remain unchanged 1, 3
• Adenomas between 2.5-4 cm that are radiologically benign and non-functional can be safely observed, according to the American Urological Association 1, 3

Required Confirmatory Steps

Imaging Characteristics Verification

• The American College of Radiology recommends confirming attenuation ≤10 HU on non-contrast CT, which is diagnostic of benign adenoma 1, 2, 4
• If attenuation is >10 HU, the National Comprehensive Cancer Network suggests performing either contrast washout CT or chemical shift MRI to confirm benignity 1, 2, 4

Functional Assessment

• The American Urological Association states that all adrenal incidentalomas require hormonal evaluation regardless of size or imaging appearance 1, 3
• The National Comprehensive Cancer Network recommends screening for subclinical Cushing syndrome with 1 mg overnight dexamethasone suppression test or 2-3 midnight salivary cortisol measurements 2, 3

Surveillance Strategy

• The American Urological Association suggests repeat imaging in 6-12 months to document stability if the adenoma is confirmed benign and non-functional 1, 2
• If growth remains <3 mm on follow-up imaging, the American Urological Association recommends discontinuing surveillance as no further imaging or functional testing is required 1

When to Consider Surgery

• The American Urological Association states that adrenalectomy should be considered only if growth exceeds 5 mm/year on follow-up imaging (after repeating functional workup) 1
• The National Comprehensive Cancer Network suggests considering adrenalectomy if there is development of hormonal hypersecretion on repeat testing or development of aggressive imaging features 1, 2, 5