Clinical Outcomes in Adrenal Incidentaloma: Experience From one Center

Abstract

To investigate the outcome in patients with adrenal incidentaloma (AI). A retrospective evaluation of 637 patients with AI referred to a tertiary center over 8 years. Radiologic and hormonal evaluations were performed at baseline. Follow-up imaging was carried out if necessary, and hormonal evaluation was performed at 24 months according to national guidelines. The mean age was 62.7 ± 11.6 years, and the mean AI size was 25.3 ± 17.0 mm at presentation. Hormonal evaluation revealed that 85.4% of all tumors were nonfunctioning adenomas, 4.1% subclinical Cushing syndrome (SCS), 1.4% pheochromocytoma, 1.4% primary hyperaldosteronism, 0.8% Cushing syndrome, 0.6% adrenocortical carcinoma, 0.3% congenital adrenal hyperplasia, 2.2% metastasis to adrenals, and 3.8% other lesions of benign origin. Bilateral tumors were found in 11%, and compared to unilateral tumors, SCS was more prevalent. Only 2 cases were reclassified during follow-up, both as SCS, but neither had had a dexamethasone suppression test performed at initial work-up. In patients diagnosed with an adrenal metastasis, 92.9% were deceased within 2 years. Excluding those with malignant tumors, 12.9% of patients died during the study period of up to 11 years due to other causes than adrenal. Most AIs were benign, but a small fraction of tumors were functional and malignant. The prognosis of patients with adrenal metastasis was extremely poor, but otherwise, the mortality rate was similar to that for the general population. Follow-up of AIs <4 cm with an initial nonfunctional profile and benign radiologic appearance appears unwarranted, but screening for congenital adrenal hyperplasia should be considered.