Renal Cystic Lesion Bosniak Classification (CT/MRI) — free guideline decision tool
Look up the malignancy risk and management for a Bosniak 2019 renal cystic-lesion category (I–IV). Instant, browser-side.
Open guideline tool →Guideline-based
Implements the decision logic from published clinical guidelines.
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No installation. Enter the patient's values and get a guideline recommendation instantly.
Data stays local
Nothing is uploaded. Results are for licensed clinicians only.
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) | I — Simple cyst |
|---|
→ManagementNo follow-up
- Category：Bosniak I: Benign (essentially 0%)
- 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
| Bosniak category (2019 version) | IV — Clearly malignant |
|---|
→ManagementSurgery
- Category：Bosniak IV: Clearly malignant (~90%)
- Management：Contains enhancing soft-tissue/nodular components: surgery (partial/radical nephrectomy), managed as renal cell carcinoma
- 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
Common questions
What is Renal Cystic Lesion Bosniak Classification (CT/MRI)?
Look up the malignancy risk and management for a Bosniak 2019 renal cystic-lesion category (I–IV). Instant, browser-side.
How is Renal Cystic Lesion Bosniak Classification (CT/MRI) calculated? What is the core formula?
I/II benign (~0%) no follow-up; IIF probably benign (~5%) imaging follow-up; III indeterminate (~50%) surgery or active surveillance; IV malignant (~90%) surgery. Enhancement = CT ≥ 20 HU or MR ≥ 15%.
When is Renal Cystic Lesion Bosniak Classification (CT/MRI) used?
Translate a Bosniak category into a no-follow-up, imaging-follow-up or surgical pathway.
What are the key clinical points for Renal Cystic Lesion Bosniak Classification (CT/MRI)?
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.
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.
How is Renal Cystic Lesion Bosniak Classification (CT/MRI) calculated in practice? Can you show a worked example?
Inputs: Bosniak category (2019 version) I — Simple cyst → Result: Management No follow-up（Category: Bosniak I: Benign (essentially 0%), 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） Inputs: Bosniak category (2019 version) IV — Clearly malignant → Result: Management Surgery（Category: Bosniak IV: Clearly malignant (~90%), Management: Contains enhancing soft-tissue/nodular components: surgery (partial/radical nephrectomy), managed as renal cell carcinoma, 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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Look up the malignancy risk and management for a Bosniak 2019 renal cystic-lesion category (I–IV). Instant, browser-side.
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