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Renal cysts
Guidelines
Key sources
The following summarized guidelines for the evaluation and management of renal cysts are prepared by our editorial team based on guidelines from the European Association of Urology (EAU 2025), the Canadian Urological Association (CUA 2023), the American Urological Association (AUA 2021), the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB 2021), and the American College of Radiology ...
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Classification and risk stratification
Bosniak classification
As per CUA 2023 guidelines:
Classify renal cysts according to the 2019 version of the Bosniak classification.
E
Arrange a multidisciplinary meeting when disagreement or doubt exists regarding the classification of a complex renal cyst if it has the potential to alter management.
E
Diagnostic investigations
Diagnostic imaging: as per CUA 2023 guidelines, obtain contrast-enhanced cross-sectional imaging to better characterize complex renal cysts identified on ultrasound.
B
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Renal function assessment
Diagnostic procedures
Biopsy
As per CUA 2023 guidelines:
Consider performing a biopsy in patients with a Bosniak IV cyst if there is a significant solid component amenable to biopsy and if the result may alter management.
E
Do not perform a biopsy of renal masses without a solid component because of low diagnostic yield.
D
Medical management
Expectant management, Bosniak I-II
As per CUA 2023 guidelines:
Do not obtain follow-up imaging in patients with a Bosniak I or II cyst.
D
Consider obtaining follow-up imaging every 6-12 months for the first year and yearly thereafter in patients with a stable Bosniak IIF cyst. Consider obtaining a follow-up of 5 years in patients with a Bosniak IIF cyst not demonstrating progression on imaging.
C
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Expectant management, Bosniak III-IV
Therapeutic procedures
Surgical interventions
Surgical excision
As per EAU 2025 guidelines:
Manage patients with Bosniak type III cysts similarly to patients with localized renal cell carcinoma or offer active surveillance.
B
Manage patients with Bosniak type IV cysts similarly to patients with localized renal cell carcinoma.
A
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Partial nephrectomy
Radical nephrectomy