Is adrenal venous sampling (AVS) required to confirm the diagnosis of a cortisol‑producing adrenal adenoma?

Adrenal Venous Sampling is NOT Required for Cortisol-Producing Adenomas

Adrenal venous sampling (AVS) is NOT required to confirm the diagnosis of a cortisol-producing adrenal adenoma and should NOT be performed in this clinical scenario. AVS is specifically reserved for primary aldosteronism, not for cortisol-secreting lesions 1.

Clear Guideline Distinction by Hormone Type

The 2023 CUA/AUA guidelines explicitly state that AVS is recommended prior to offering adrenalectomy in patients with primary aldosteronism (Recommendation 7.2), but make no such recommendation for cortisol-secreting adenomas 1. This distinction is critical and consistent across multiple guideline reviews 1.

Diagnostic Pathway for Cortisol-Producing Adenomas

For suspected cortisol-secreting adenomas, the diagnostic approach is fundamentally different:

• Screen with 1 mg dexamethasone suppression test as the preferred method for identifying autonomous cortisol secretion 1
• Confirm laterality with imaging alone (non-contrast CT showing <10 HU for adenoma, or chemical-shift MRI/washout CT for indeterminate lesions) 1
• Proceed directly to unilateral adrenalectomy for patients with unilateral cortisol-secreting masses and clinically apparent Cushing's syndrome 1

Why AVS is Reserved for Aldosterone Excess

AVS is technically challenging and specifically designed to lateralize aldosterone production because bilateral adrenal hyperplasia and unilateral aldosterone-producing adenomas cannot be reliably distinguished by imaging alone 1. The AACE/AAES guidelines recommend AVS in the majority of primary aldosteronism patients, even those with masses well visualized on imaging, because the therapeutic decision (surgery vs. medical management) depends entirely on lateralization 1.

In contrast, cortisol-producing adenomas are typically unilateral and can be identified by the combination of biochemical testing and imaging characteristics without the need for invasive venous sampling 1.

Important Caveats and Special Circumstances

Bilateral Adrenal Masses with Cortisol Excess

The one scenario where AVS may have utility for cortisol excess is in patients with bilateral adrenal masses and ACTH-independent autonomous cortisol secretion where determining unilateral vs. bilateral disease would change surgical management 2, 3. Research demonstrates that AVS can distinguish between unilateral and bilateral cortisol secretion with high specificity (95-100% for unilateral disease with specific cortisol ratio cutoffs) 2. However, this remains a research application and is not part of standard guideline recommendations 1.

Co-Secreting Tumors

Be aware that aldosterone- and cortisol-co-secreting tumors exist and autonomous cortisol production can confound AVS interpretation in primary aldosteronism cases 4, 5. If a patient has both primary aldosteronism and evidence of cortisol excess (adenoma >2.5 cm, non-suppressible cortisol on dexamethasone testing, or elevated hybrid steroids like 18-hydroxy-cortisol), this should be recognized before proceeding with AVS 4. Concurrent cortisol hypersecretion can reduce aldosterone-to-cortisol ratios on the affected side and increase them on the contralateral side, potentially leading to misclassification 5.

Clinical Algorithm

For a patient with suspected cortisol-producing adenoma:

1. Perform 1 mg dexamethasone suppression test to confirm autonomous cortisol secretion 1
2. Obtain non-contrast CT to characterize the adrenal mass (HU <10 confirms benign adenoma) 1
3. If clinically apparent Cushing's syndrome is present with unilateral mass: proceed directly to minimally invasive unilateral adrenalectomy 1
4. If mild autonomous cortisol secretion: consider adrenalectomy in younger patients with progressive metabolic comorbidities after shared decision-making 1
5. Do NOT perform AVS unless there are bilateral masses and uncertainty about laterality that would change surgical planning 2, 3

For a patient with primary aldosteronism:

1. Screen with aldosterone-to-renin ratio in patients with hypertension and/or hypokalemia 1
2. Confirm with saline suppression testing 1
3. Perform AVS prior to adrenalectomy to lateralize aldosterone production 1

The fundamental principle is that imaging plus biochemical testing is sufficient for cortisol-producing adenomas, while AVS is essential for aldosteronism to distinguish surgical from medical management 1.