Radiological localizing techniques in adrenal tumors

The characterisation of adrenal lesions is a common radiological dilemma. Incidental adrenal lesions are commonly detected with computed tomography (CT), and lesion characterisation is critical. The prevalence of incidental adrenal lesions has been reported to be 2.3% at autopsy and 0.5-2% with abdominal CT. Such lesions are likely to be seen with increasing frequency given the expanding use of radiological imaging in clinical practice. Although the majority of adrenal lesions are benign, in patients with an extra-adrenal primary cancer the probability of an adrenal mass being a metastasis is 52%. Unfortunately, there may be significant overlap between the imaging appearances of benign lesions such as lipid-poor adenomas and malignant lesions, particularly metastases and small adrenal carcinomas. This review highlights recent advances in radiological imaging of adrenal lesions and we discuss the relative merits of CT and magnetic resonance imaging to aid the identification of benign and malignant adrenal lesions and their roles, in combination with biochemical and clinical data, in recognizing common pathologies such as adrenal adenoma, phaeochromocytoma, carcinoma and metastases. We also discuss the radiological characteristics of rarer adrenal lesions including lymphoma, neuroblastic tumours (neuroblastoma, ganglioneuroblastoma, and ganglioneuroma), lipomatous tumours (myelolipoma, angiolipoma, teratoma, lipoma and liposarcoma), in addition to hemangioma, hemangiosarcoma and leiomyosarcoma.