Primary aldosteronism (PA) remains a significant challenge in clinical practice, especially when identifying patients for surgical cure. Adrenal vein sampling (AVS) serves as the gold standard for lateralization, but its technical complexity often leads clinicians toward cross-sectional imaging. However, a recent study reveals significant limitations in Primary Aldosteronism Imaging Accuracy. These findings suggest that imaging results often fail to align with the true pathological sources of aldosterone excess.

The retrospective cohort study, led by Mermejo and colleagues, analyzed 173 patients who underwent unilateral adrenalectomy between 2012 and 2024. Researchers compared blinded cross-sectional imaging interpretations with aldosterone synthase (CYP11B2) immunohistochemistry (IHC). Interestingly, only 31% of patients showed a single corresponding lesion on both imaging and IHC. Furthermore, the overall discordance rate between imaging and the functional IHC map was a staggering 47.4%.

Primary Aldosteronism Imaging Accuracy and Clinical Implications

These findings demonstrate that morphological nodules seen on CT or MRI do not always represent the actual source of aldosterone production. In many cases, imaging showed additional non-functional nodules or bilateral involvement that did not match the CYP11B2-positive foci. Consequently, relying solely on imaging for surgical guidance could lead to inappropriate adrenalectomies or missed pathologies. The study also noted that KCNJ5 mutations were more common in concordant cases. Conversely, CACNA1D mutations appeared more frequently in the discordant group.

Additionally, the high rate of discrepant findings underscores the importance of functional assessment. If surgeons target the wrong nodule based on inaccurate imaging, patients may not achieve a biochemical cure. Therefore, clinicians should prioritize AVS or emerging molecular imaging techniques to ensure precise localization before intervention.

Frequently Asked Questions

Why is cross-sectional imaging often unreliable for primary aldosteronism?

Imaging methods like CT or MRI identify anatomical structures but cannot determine hormonal activity. Many patients have non-functional incidentalomas or microscopic aldosterone-producing foci that are too small for traditional imaging to detect.

What is the clinical significance of CYP11B2 IHC?

CYP11B2 immunohistochemistry specifically stains the enzyme responsible for aldosterone production. It allows pathologists to confirm if a resected nodule was indeed the source of hyperaldosteronism, providing a functional validation that imaging lacks.

How does this study change the management of lateralized PA?

This research cautions against using imaging as the sole guide for surgery. It reinforces the necessity of functional lateralization and highlights the potential for future molecular imaging to bridge the gap between anatomy and function.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or establish a doctor-patient relationship. Always consult a qualified healthcare professional for diagnosis and treatment. Refer to the latest local and national guidelines for clinical practice.

References

Mermejo LM et al. Aldosterone Synthase Expression vs. Cross-Sectional Imaging in Lateralized Primary Aldosteronism. J Clin Endocrinol Metab. 2026 May 06. doi: undefined. PMID: 42089263.

Funder JW et al. The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2016;101(5):1889-1916.

Årstad E et al. Adrenal Aldosterone Synthase Expression Imaging in Primary Aldosteronism. N Engl J Med. 2025;393(21):2168-2170.