Diagnosis and management of cystic renal masses

Most cystic renal masses are easily diagnosed as benign simple cysts. Some complex cysts, however, include both benign and malignant lesions and often require further evaluation. The Bosniak classification system is widely accepted to evaluate these cystic renal masses. This classification system categorizes cystic renal masses into five categories according to the CT findings and also advocates management for each category. We showed an appropriate CT protocol for proper categorization and the typical CT findings for each category. Furthermore, we reviewed the role of MRI in the assessment of cystic renal masses and how to perform follow-up examinations for the management of Category IIF lesions.