Endocrine Abstracts

Background: Adrenal incidentalomas (AIs) detected on pre surgical scans often present a logistical challenge due to the pressing need for preoperative exclusion of a phaeochromocytoma. Our local guideline recommends endocrinology referral for all AIs for further investigations, including pre clinic 24-hr urine metadrenalines. This approach can be time-consuming, particularly for patients awaiting unrelated surgery.

Methods: Our review included all AIs identified within our centre over a 2-year period (from 1/1/2021 to 31/12/2022). All AIs underwent unselected screening for phaeochromocytoma, including urine metadrenaline (MN) & normetadrenaline (NMN) analysis, followed by measurements of plasma MN and NMN concentrations in those with raised 24-hr urine MN/NMN concentrations.

Results: Initial analysis revealed 13 patients with elevated 24-hr urine NMN or MN levels, with 5 patients confirming elevated levels on 2 separate occasions. Subsequently only 2/13 (15.4%) patients had confirmed raised plasma normetadrenaline and/or metadrenaline concentrations, suggesting possibility of a phaeochromocytoma. On retrospective review, both these patients also had an AI with raised HU (>10 HU; recommended diagnostic threshold for pheochromocytoma screening for AIs).

Conclusion: Our ongoing review aims to validate the guidance that early adoption of the HU approach as an initial screening tool for adrenal incidentalomas is cost-effective and clinically safe. However, practical application of this approach requires a standardised multidisciplinary assessment for all AIs including careful evaluation of all imaging, prior to undertaking endocrinology assessment, to optimise resource utilisation in clinical practice.