Endocrine Abstracts

Background: Current practice of monitoring adrenal incidentalomas with biochemical follow-up and repeat imaging studies is under review by the ESE.

Following an audit presented in 2015, we proposed that this extensive follow-up was unnecessary in radiologically benign lesions, as neither functional nor malignant lesions were present in this subgroup.

Methods: A retrospective review of the same cohort of 145 patients with adrenal incidentalomas (January 2013 – January 2015), evaluated the outcome of repeat imaging and biochemistry.

Functionality was determined by overnight dexamethasone suppression test (cortisol >140 defines autonomous cortisol secretion), renin: aldosterone, serum DHEAS and 24 h urinary metanephrines.

Results: Eighty-five percent were non-functional adenomas, 6% were benign lesions (e.g. angiomyolipomas). 0.7% had Conn’s adenoma with raised renin:aldosterone. No patients had autonomous cortisol secretion. 4% were phaeochromocytomas – all were suspected on imaging and had raised urinary metanephrines; one had elevated DHEAS in addition. 4% were malignant lesions – 1.4% adrenocortical carcinomas (ACC), 2.1% metastases and 0.7% sarcoma.

Forty-eight percent of images were typical of benign adenomas, of which 70% had repeat imaging at an average time interval of 18 months – none changed. 45.5% of scans were indeterminate, however on further imaging 80% were considered benign adenomas with no change over an average time interval of 13 months. 3.5% of scans appeared malignant, of which 60% were phaeochromocytomas and 20% ACCs. The remainder were non-adrenal. 3% of scans were angiomyolipomas.

Mean duration from detection scan to most recent biochemical testing was 9 months, during which, 91% of incidentalomas remained non-functional. 23% of the cohort had repeat biochemistry; none progressed from non-functional to functional lesions.

Conclusion: We maintain that, follow-up is unnecessary for adrenal incidentalomas that are consistent with benign adenomas on initial imaging, and non-functional. Transformation to malignant or functional lesions is rare.