Complex renal cystic masses: current standards and controversies

Area of Science:

• Urology
• Radiology
• Oncology

Background:

• The Bosniak classification system is a key preoperative tool for renal cystic masses.
• Despite its utility, interobserver variability and misclassification of benign masses as malignant (especially Bosniak III) persist.

Purpose of the Study:

• To identify specific imaging findings that differentiate Bosniak IIF from Bosniak III renal cystic lesions.
• To explore the potential for developing nomograms or risk calculators to improve Bosniak classification accuracy.

Main Methods:

• Review of imaging characteristics of complex renal cystic masses.
• Analysis of factors influencing the distinction between Bosniak IIF and III categories.
• Evaluation of the role of radiographic growth versus internal architectural changes and enhancement in malignancy detection.

Main Results:

• Interobserver variability remains a significant limitation in the Bosniak classification system.
• A substantial proportion of Bosniak III masses are benign, highlighting the need for improved diagnostic accuracy.
• Changes in internal architecture and the presence of enhancement are critical indicators of malignancy in active surveillance.

Conclusions:

• Refining the Bosniak classification requires identifying critical variables to improve preoperative diagnosis of renal cystic masses.
• Distinguishing between Bosniak IIF and III lesions necessitates a focus on specific imaging features beyond simple growth.
• Developing risk calculators could help reduce unnecessary surgeries for complex renal cysts.