Endocrine Abstracts

Context: Phaeochromocytomas are rare, but potentially fatal, neoplasms. The diagnosis and localization of phaeochromocytoma can be challenging and recently there has been some debate regarding the role for adrenal venous sampling (AVS). The utility of AVS in this setting is hampered by a lack of normative value data for adrenal vein catecholamine concentrations and the reliability of lateralization ratios. We sought to address these concerns by analyzing AVS catecholamine concentrations from patients who did not have phaeochromocytoma.

Design/setting: Eighteen patients underwent successful AVS for evaluation of possible cortisol-producing adrenal masses. All had normal 24 h urinary excretion of fractionated catecholamines and metanephrines.

Results: There was a wide range of catecholamine concentrations in both the right (epinephrine 389–118 326 pg/ml; norepinephrine 156–11 193 pg/ml) and left (epinephrine 113–9327 pg/ml; norepinephrine 229–2216 pg/ml) adrenal veins. The right adrenal vein to left adrenal vein epinephrine gradient was as high as 83:1 (median, 2.1:1; P<0.02); the majority of right-to-left adrenal vein epinephrine ratios were greater than one. Although less striking, similar findings were also seen for norepinephrine.

Conclusions: This report provides a reference range for adrenal vein catecholamine concentrations in non-phaeochromocytoma patients and illustrates the wide variation in epinephrine and norepinephrine concentrations. Epinephrine and norepinephrine concentrations are statistically significantly higher in the right versus the left adrenal vein; in the case of epinephrine, up to a 83-fold difference was found between the right and left adrenal veins. This wide range in variability limits the utility of AVS in the diagnosis or localization of phaeochromocytoma.