Adrenal incidentalomas: risk of adrenocortical carcinoma and clinical outcomes

Abstract

Introduction: The number of incidentally discovered adrenal lesions is increasing due to the widespread use of abdominal imaging. Although most incidentalomas are benign, larger suspicious lesions will require adrenalectomy. The aim of this study is to determine the risk of malignancy in patients undergoing surgery for adrenal incidentaloma; and to compare clinical outcomes in those with adrenocortical carcinoma (ACC) based on the mode of presentation.

Methods: A retrospective study of consecutive patients who underwent adrenalectomy between 1995 and 2008 was performed. Data were retrieved from a prospectively maintained adrenal tumor database. Those with adrenal incidentaloma were selected and histopathology reviewed. All patients with ACC (presenting with symptoms or incidentally) during the same time period were identified and clinical outcomes compared.

Results: Adrenalectomy was performed in 274 patients of whom 73 (27%) were characterized pre-operatively as incidentaloma. Benign, non-functioning adrenocortical adenoma was the most common histopathological finding (46 patients, 63%). There was a trend (P = 0.08) towards increased survival amongst the seven patients with ACC presenting incidentally compared to the nine patients with symptomatic ACC.

Conclusions: Adrenal incidentalomas have a small but important risk of malignancy. ACC presenting as incidentaloma appear to have a more favorable prognosis than symptomatic or functioning ACC.