Endocrine Abstracts

Adrenal incidentalomas are a common clinical dilemma with increasing utilisation of cross-sectional imaging modalities. The aims of management include: i) exclusion of possible malignancy and ii) identification of hormonally active lesions.

Our unit has adopted AACE guidelines, including a screen for adrenal androgen hypersecretion. This audit aimed to review the utility of such an approach.

We identified case notes of 145 consecutive adrenal incidentalomas referred to Endocrinology from January 2013 to January 2015. All were subject to radiological scrutiny by a dedicated radiologist, whilst Endocrine investigations, including two 24 h urinary metanephrines, 1 mg overnight dexamethasone suppression test, renin:aldosterone ratio and DHEAS were arranged, together with electrolytes and blood pressure.

Radiologically, 75% percent were considered to be benign adrenal adenomas on the basis of either CT density (<10 HU), CT contrast washout at 10 min (>60%) or in and out of phase MRI. 0.02% were myolipomas and 3.5% phaeochromocytomas. 14% were indeterminate and referred for further investigation or surgery. Of those which were radiologically indeterminate, 25% were resected (four benign adenomas and one ganglioneuroma), 40% underwent follow-up imaging and investigations and were later shown to be non-functional benign adenomas, one was biopsied and found to be an ACC. The remainder either did not attend follow up or were not further investigated due to patient comorbidity.

From a functional perspective, we identified five phaeochromocytomas, all of whom had imaging studies inconsistent with a benign adenoma and raised urinary metanephrines. Six had a 0900 h cortisol of >100 following 1 mg dexamethasone, none of whom had symptoms/signs consistent with cortisol excess. Four were deemed to be normal after further investigation. The remaining two were on medication which could have led to the excess. Two males had elevated DHEAS levels, both of whom had abnormal imaging. One proved to have a phaeochromocytoma. There were two abnormal renin:aldosterone ratios. Both were subsequently confirmed to have Conn’s adenomas. 91% of the cohort was hormonally inactive.

On the basis of this audit, we are concerned that adrenal incidentalomas are currently over-investigated. In patients with no symptoms/signs of an underlying endocrinopathy, normal blood pressure, normokalaemia, and imaging consistent with a benign adenoma, universal endocrine investigation is largely unrewarding.