Association between Tumor Size and Malignancy Risk in Hormonally Inactive Adrenal Incidentalomas

Abstract

Introduction Adrenal incidentalomas (AI) are adrenal masses that are discovered during radiological examinations conducted for other reasons. In this study, we focused on the pathological and radiological properties of nonfunctional AI(NFAI) and the association with malignancy risk in our clinical series. Methods A total of 186 patients underwent adrenalectomy between 2010 and 2017; of these, 76 (40.8%) patients with non-functional AI were included in the current study. The radiological and pathologic characteristics of these AIs were retrospectively analyzed to determine the malignancy rate. Results There were 22 (28.9%) male and 54 (71.1%) female patients with nonfunctional AI included in this study. The median age was 55 (range: 24-85) years. Of the patients included, 37 (48.6%) had AI on the left and 39 (51.3%) had AI on the right adrenal gland. Sixty-one (80.2%) cases were treated laparoscopically, four (5.3%) required conversion to open surgery due to intraoperative difficulties such as bleeding and adhesions, and 11 (14.4%) were managed with open adrenalectomy. The rate of malignancy in the tumors with diameters of <4 cm, 4-6 cm, and >6 cm was found to be 0%, 2.9%, and 13.6%, respectively. Conclusions Determining the ideal cutoff value for surgical indication in an NFAI is challenging. Besides the malignancy risk, the rate of silent pheochromacytomas must be taken into account in the surgical decision.

Keywords: adrenal incidentalomas; adrenocortical cancer; pheochromocytoma.

Figure 1. Flow chart of the study group based on AACE/AAES guidelines (i.e., the reasons for surgery in 76 patients with hormonally inactive AI)

AI: adrenal Incidentaloma, CT: computed tomography, MRI: magnetic resonance imaging, AACE: American Association of Clinical Endocrinologists, AAES: American Association of Endocrine Surgeons