Introduction

An adrenal “incidentaloma” is an adrenal mass, 1 cm or more in diameter, which is incidentally discovered during a radiologic examination performed for indications other than an evaluation for adrenal disease. With the widespread use of abdominal ultrasonography, multi-detector row computed tomography (MDCT), magnetic resonance (MR) imaging, and positron emission tomography (PET) the incidence of adrenal incidentalomas has substantially increased. According to recent studies, the overall frequency of adrenal masses is approximately 4% at abdominal MDCT [1], which compares favorably with the 6% prevalence rate reported in a large autopsy study [2]. Although the majority of adrenal incidentalomas are clinically benign adenomas, other frequently reported diagnoses include metastases, pheochromocytomas, and adrenocortical carcinomas. The differential diagnosis between benign and malignant adrenal masses has become a common dilemma, which is compounded in patients with known or suspected of having an extra-adrenal malignancy, where approximately 50% of incidentally detected adrenal lesions are metastatic disease [3].