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🫘 Renal Cystic Lesion Bosniak Classification (CT/MRI)

UseTranslate a Bosniak category into a no-follow-up, imaging-follow-up or surgical pathway.

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SourceSilverman SG, et al. Bosniak Classification of Cystic Renal Masses, Version 2019. Radiology 2019

Runs locally in your browser (no PHI uploaded). For licensed clinicians — not a substitute for clinical judgement.
Stored on this device for revisit reminders

This-shift next steps

After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.

Scene next step
📋imaging radsOpen scene pack →
Related scores
Matching pathway
🧭orads_usOpen pathway →
Score + version; reference only — not a substitute for care · no HIS write

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Methodology · worked example, guidelines & full notes
Clinical takeaway

The 2019 version unified the enhancement definition (CT ≥ 20 HU or MR ≥ 15%).

When to use

Translate a Bosniak category into a no-follow-up, imaging-follow-up or surgical pathway.

How it works

I/II benign no follow-up; IIF probably benign imaging follow-up; III indeterminate surgery or active surveillance; IV malignant surgery. Enhancement = CT ≥ 20 HU or MR ≥ 15%.

Key points

  • The 2019 version unified the enhancement definition (CT ≥ 20 HU or MR ≥ 15%).
  • Morphologic upgrade on follow-up strongly predicts malignancy and warrants reclassification.
  • Biopsy of cystic lesions is generally not recommended (except category IV).
  • Category III management balances surgery vs active surveillance by age and comorbidity.

References

Worked calculation

The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.

Bosniak category (2019 version)IIF — Probably benign (follow-up)

→ManagementImaging follow-up

  • Category：Bosniak IIF: Probably benign
  • Management：Smooth minimally thick (3 mm) enhancing wall/septa, or many (≥ 4) thin enhancing septa, etc.: imaging follow-up (e.g. 6, 12 months, then yearly to 5 years); reclassify if morphology upgrades
  • Enhancement criteria：2019 unified enhancement definition: CT attenuation increase ≥ 20 HU vs unenhanced, or MR signal increase ≥ 15%; thin = ≤ 2 mm, minimally thick = 3 mm, many = ≥ 4 septa
Bosniak category (2019 version)I — Simple cyst

→ManagementNo follow-up

  • Category：Bosniak I: Benign
  • Management：Simple cyst (thin ≤ 2 mm smooth wall, homogeneous simple fluid, no septa/calcification; wall may enhance): no follow-up
  • Enhancement criteria：2019 unified enhancement definition: CT attenuation increase ≥ 20 HU vs unenhanced, or MR signal increase ≥ 15%; thin = ≤ 2 mm, minimally thick = 3 mm, many = ≥ 4 septa
Verification & sources · governance
FAQ

Frequently asked questions

What are the limits and cautions when using Renal Cystic Lesion Bosniak Classification (CT/MRI)?
For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
Does Renal Cystic Lesion Bosniak Classification (CT/MRI) upload patient data? Where is it calculated?
Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
How is Renal Cystic Lesion Bosniak Classification (CT/MRI) calculated in practice? Can you show a worked example?
Inputs: Bosniak category (2019 version) IIF — Probably benign (follow-up) → Result: Management Imaging follow-up（Category: Bosniak IIF: Probably benign, Management: Smooth minimally thick (3 mm) enhancing wall/septa, or many (≥ 4) thin enhancing septa, etc.: imaging follow-up (e.g. 6, 12 months, then yearly to 5 years); reclassify if morphology upgrades, Enhancement criteria: 2019 unified enhancement definition: CT attenuation increase ≥ 20 HU vs unenhanced, or MR signal increase ≥ 15%; thin = ≤ 2 mm, minimally thick = 3 mm, many = ≥ 4 septa） Inputs: Bosniak category (2019 version) I — Simple cyst → Result: Management No follow-up（Category: Bosniak I: Benign, Management: Simple cyst (thin ≤ 2 mm smooth wall, homogeneous simple fluid, no septa/calcification; wall may enhance): no follow-up, Enhancement criteria: 2019 unified enhancement definition: CT attenuation increase ≥ 20 HU vs unenhanced, or MR signal increase ≥ 15%; thin = ≤ 2 mm, minimally thick = 3 mm, many = ≥ 4 septa）
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