From the Guidelines
The laboratory workup for adrenal adenoma should include a comprehensive hormonal evaluation and imaging studies, as recommended by the most recent guidelines 1.
Key Components of the Workup
- Initial hormonal testing should assess for excess cortisol with a 1mg overnight dexamethasone suppression test or 24-hour urinary free cortisol, as suggested by the guidelines 1.
- Aldosterone overproduction should be evaluated with plasma aldosterone concentration and plasma renin activity, calculating the aldosterone-to-renin ratio, especially in patients with hypertension and/or hypokalemia 1.
- Catecholamine excess should be screened with plasma free metanephrines or 24-hour urinary metanephrines and catecholamines, particularly if the adrenal mass displays >10 HU on non-contrast CT or if there are signs/symptoms of adrenergic excess 1.
Imaging Studies
- A dedicated adrenal CT scan with contrast is typically the first-line imaging study to characterize the adenoma's size, density, and enhancement pattern 1.
- MRI may provide additional information in certain cases, especially when the initial imaging is not consistent with a benign lesion or when there's evidence of hormone hypersecretion 1.
Additional Considerations
- For patients with hypertension, a complete metabolic panel including potassium levels is essential, as it can help identify primary aldosteronism or other metabolic disorders 1.
- If Cushing's syndrome is suspected, additional tests like late-night salivary cortisol and ACTH levels can help determine if the hypercortisolism is ACTH-dependent or independent 1.
- The decision for surgical intervention versus surveillance should be based on the comprehensive workup, taking into account the size of the adenoma, its hormonal activity, and the patient's overall clinical condition, as emphasized by the guidelines 1.
From the Research
Adrenal Adenoma Lab Workup
- The lab workup for adrenal adenoma typically involves a dexamethasone suppression test to determine if the adrenal mass is hormonally active 2, 3, 4, 5, 6
- The dexamethasone suppression test is used to diagnose autonomous cortisol secretion, which can be present in up to 30-50% of patients with adrenal incidentalomas 2, 4
- An unenhanced CT attenuation value of 10 Hounsfield units or less can exclude adrenocortical carcinoma and pheochromocytoma 3
- Testing for hyperaldosteronism should be performed in hypertensive and/or hypokalemic patients, and testing for sex hormones and steroid precursors should be performed in patients with clinical features suggestive of adrenocortical carcinoma 3
- The 1mg-dexamethasone suppression test is a reliable marker of glucocorticoid excess and cardiometabolic risk in patients with adrenal incidentalomas, but its diagnostic accuracy can be improved by combining it with urinary steroid profile and serum DHEAS 6
Dexamethasone Suppression Test
- The dexamethasone suppression test is the standard method to diagnose autonomous cortisol secretion (ACS) from an adrenal adenoma 5
- A cortisol level > 1.8 µg/dL after the dexamethasone suppression test is indicative of ACS 5, 6
- The test has a positive, but modest, correlation with urinary glucocorticoid excretion, and its diagnostic accuracy can be improved by combining it with urinary steroid profile and serum DHEAS 6
Urinary Steroid Profile
- The urinary steroid profile can be used to improve the diagnostic accuracy of the dexamethasone suppression test for predicting ACS-related comorbidities 6
- The profile can be determined by gas chromatography coupled to mass spectrometry, and it can provide information on the excretion of glucocorticoid metabolites such as β-cortolone, tetrahydro-11-deoxycortisol, α-cortolone, α-cortol, tetrahydrocortisol, and tetrahydrocortisone 6