Accuracy of CT scanning and adrenal vein sampling in the pre-operative localization of aldosterone-secreting adrenal adenomas

In primary hyperaldosteronism, it is important to distinguish between unila teral and bilateral disease, as management strategies differ. In the period 1983-95, we identified 34 patients with primary hyperaldosteronism. Follow ing further investigations, a diagnosis of aldosterone-secreting adenoma wa s made in 17 patients, and surgery was performed. Computed tomography clear ly localized an apparent adenoma (discrete adenoma = 1 cm diameter; normal contralateral gland) in only 10 of these patients (59%); two of these 'aden omas' were subsequently shown to be hyperplastic glands without adenomas. H istological examination showed adrenal adenomas in the remaining 15 patient s. An 'adenoma' also appeared to be clearly localized in 3/17 patients late r classified as having bilateral adrenal hyperplasia by adrenal vein sampli ng. CT scanning, therefore clearly localizes adenomas in only 50% of histol ogically proven cases, and can also produce misleading results. Adrenal vei n sampling results altered our management approach in one third of cases. O n the basis of our detailed results we would recommend surgery if there is clear evidence of unilateral aldosterone secretion along with CT findings w hich may not be strictly localizing but are in keeping with the dominant si de on adrenal vein sampling. The decision to refer for surgery in primary h yperaldosteronism can be difficult, and we would caution against too heavy a reliance on CT results when recommending adrenalectomy, and suggest that adrenal vein sampling should remain a routine part of the investigation of patients with primary hyperaldosteronism.