Who Should Be Screened for Adrenal Incidentaloma?
All patients with an incidentally discovered adrenal mass on imaging performed for reasons unrelated to suspected adrenal disease require screening—this is the definition of an adrenal incidentaloma and mandates evaluation. 1, 2
Universal Screening Requirements
Every patient with an adrenal incidentaloma must undergo:
Autonomous cortisol secretion screening using a 1 mg overnight dexamethasone suppression test (1 mg at 11 PM, measure serum cortisol at 8 AM), regardless of clinical symptoms or imaging characteristics 1, 3, 4
Pheochromocytoma screening with plasma free metanephrines or 24-hour urinary fractionated metanephrines if the mass shows >10 HU on non-contrast CT OR if any signs/symptoms of catecholamine excess are present 1, 3, 5
Primary aldosteronism screening with aldosterone-to-renin ratio in all patients who have hypertension and/or hypokalemia 1, 3, 5
Exception to Pheochromocytoma Screening
The only scenario where you can skip pheochromocytoma screening is when the mass demonstrates unequivocal benign features on unenhanced CT (HU <10) AND the patient has no signs or symptoms of adrenergic excess 1. This is a narrow exception—when in doubt, screen.
Additional Screening in Specific Scenarios
Androgen excess testing (DHEA-S, testosterone, 17-hydroxyprogesterone, androstenedione) is required when clinical virilization signs are present OR when adrenocortical carcinoma is suspected 1, 3, 4
Bilateral adrenal masses require measurement of serum 17-hydroxyprogesterone to exclude congenital adrenal hyperplasia, in addition to evaluating each mass individually 1, 3, 5
Critical Context
The prevalence data justifies universal screening: approximately 5.3% of adrenal incidentalomas are cortisol-secreting adenomas, 5.1% are pheochromocytomas, and 1% are aldosterone-secreting adenomas 3, 4. Up to 30-50% may have mild autonomous cortisol secretion, which carries increased cardiovascular morbidity and metabolic risk 6.
Common Pitfalls to Avoid
Never skip hormonal evaluation even for radiologically benign-appearing masses, as imaging characteristics cannot reliably predict functional status 4, 7
Never perform adrenal biopsy before excluding pheochromocytoma—this can precipitate life-threatening hypertensive crisis 5, 4
Do not assume small size equals non-functional—hormone hypersecretion occurs independent of mass size and requires biochemical screening 1, 8
Medications can interfere with hormone testing results; hold interfering medications when possible before testing 3, 4