The Bosniak renal cyst classification: 25 years later.

In the past 25 years, there have been continuous advances in the diagnosis of disease throughout the body owing to the introduction of new technology and the experience gained with its use. However, the imaging and evaluation of complicated cystic lesions of the kidneys frequently remains a difficult problem. The classification of renal cystic lesions suggested 25 years ago, now referred to as the Bosniak renal cyst classification, remains pertinent to the diagnosis and management of these difficult-to-diagnose complicated cystic masses.