On CT urogram (CTU), a renal mass showing 15 HU enhancement after contrast (>10 HU considered significant enhancement) should be classified using which scoring system to determine surgical vs. surveillance management?
- A TNM staging system
- B RENAL nephrometry score
- C Bosniak classification (for cystic renal masses) ✓
- D LI-RADS for renal masses
Explanation
The Bosniak classification is used for cystic renal masses on CT or MRI. Enhancement >20 HU after contrast (or >10 HU in some protocols) indicates a complex cystic mass requiring Bosniak classification: Bosniak I (simple cyst, 0% malignancy) → II (minimally complex, <3%) → IIF (follow-up, ~5%) → III (complex, ~50%) → IV (clearly malignant, >90%). Bosniak III and IV lesions typically require surgery or ablation. RENAL nephrometry score (Radius, Exophytic/endophytic, Nearness to collecting system, Anterior/posterior, Location relative to polar line) guides surgical planning for solid masses. TNM is for pathologically confirmed malignancy staging.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.