Advances in our understanding of the prognosis of adrenal incidentaloma.

INTRODUCTION: As cross-sectional abdominal imaging is used increasingly, adrenal incidentaloma (AI) are being found frequently and present a clinical dilemma. The vast majority are benign and non-functioning, but a minority represent incidentally found functional or malignant tumours. In this review we summarise the current clinical, biochemical and radiological investigation of AI and discuss recent advances that differentiate clinically inconsequential lesions from functional and/or malignant AI. Areas covered: Prevalence, natural history, biochemical and radiological assessment, indications for surgery and surgical provision. Expert commentary: Well established work-up of AI usually enables benign, non-functioning lesions to be differentiated from functioning and/or malignant AI. In indeterminate lesions recent advances in work-up such as urine steroid profiles measured by gas chromatography /mass spectrometry and functional imaging with 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) in addition to standard investigations have improved characterisation of these lesions. The management of AI showing mild autonomous hypercortisolism without overt features of Cushing's syndrome remains controversial and is discussed in this review.