Bosniak Classification version 2019: validation and comparison to original classification in pathologically confirmed...

Area of Science:

• Urology
• Radiology
• Oncology

Background:

• The Bosniak classification system categorizes cystic renal masses based on imaging features.
• Accurate classification is crucial for determining appropriate management and prognosis.
• The v2019 update aimed to refine definitions and improve diagnostic performance.

Purpose of the Study:

• To evaluate the accuracy and inter-observer agreement of the Bosniak Classification v2019 definitions.
• To compare the v2019 classification with the original Bosniak classification in pathologically confirmed cystic renal masses.
• To assess the association of specific Bosniak v2019 features with malignancy.

Main Methods:

• Retrospective analysis of 73 pathologically confirmed cystic renal masses (57 malignant, 16 benign).
• Evaluation by three blinded radiologists using Bosniak v2019 and original classifications.
• Comparison of classification results with histological findings.

Main Results:

• Bosniak v2019 showed slightly improved inter-observer agreement compared to the original classification.
• Wall and septa thickness (≥ 3 mm) were associated with malignancy.
• The number of septa was not associated with malignancy.
• Malignancy proportions overlapped between Bosniak v2019 classes IIF, III, and IV based on features like "irregularity" and "nodule".

Conclusions:

• Bosniak v2019 definitions for wall/septa thickness and protrusions are associated with malignancy.
• The v2019 classification categorizes a higher proportion of malignant masses in Class IIF.
• A threshold of ≥ 3 mm for wall/septa thickness improved diagnostic accuracy.