Bosniak classification of cystic renal masses, version 2019: interpretation pitfalls and recommendations to avoid misclassification

The purpose of this review is to describe the potential sources of variability or discrepancy in interpretation of cystic renal masses under the Bosniak v2019 classification system. Strategies to avoid these pitfalls and clinical examples of diagnostic approaches are also presented. Potential pitfalls in the application of Bosniak v2019 are divided into three categories: interpretative, technical, and mass related. An organized, comprehensive review of possible discrepancies in interpreting Bosniak v2019 cystic masses is presented with pictorial examples of difficult clinical cases and proposed solutions. The scheme provided can guide readers to consistent, precise application of the classification system. Radiologists should be aware of the possible sources of misinterpretation of cystic renal masses when applying Bosniak v2019. Knowing which features and types of cystic masses are prone to interpretive errors, in addition to the inherent trade-offs between the CT and MR techniques used to characterize them, can help radiologists avoid these pitfalls.

Automated summary

This review describes potential sources of variability in interpreting cystic renal masses under the Bosniak v2019 classification system, categorizing pitfalls into interpretative, technical, and mass-related aspects. Strategies and clinical examples are provided to avoid these pitfalls, guiding radiologists to achieve consistent and precise application of the classification system. Radiologists should be aware of sources of misinterpretation when applying Bosniak v2019, understanding features prone to errors and trade-offs between CT and MR techniques.