A solid enhancing renal mass without macroscopic fat is renal cell carcinoma until proven otherwise; report size, subtype clues, nephrometry for nephron-sparing surgery, renal vein and IVC thrombus, and the staging.
Orient first
- A lesion is solid when it enhances measurably against its own unenhanced series; the thresholds differ between CT and MRI (verify local thresholds).
- Clear cell RCC is hypervascular and heterogeneous; papillary is hypovascular and homogeneous; chromophobe and oncocytoma may show a central scar.
- Macroscopic fat without calcification means angiomyolipoma (see its own page).
Acquire the study
- Unenhanced, corticomedullary and nephrographic phases (1–3 mm) with coronal reformats; excretory if the collecting system is involved.
The manoeuvre
- Measure enhancement in HU with the same ROI on unenhanced and nephrographic phases.
- Size in cm in three planes; exophytic vs endophytic, relation to the collecting system — for R.E.N.A.L. nephrometry.
- Renal vein and IVC: expanded vessel with enhancing tumour thrombus; the upper level relative to the hepatic veins and right atrium.
- Perinephric fat and Gerota fascia invasion; ipsilateral adrenal.
- Nodes, lungs (chest CT), bone.
What confirms it
- A solid enhancing renal mass without macroscopic fat, with size and venous extent stated.
What licenses you to exclude it
- No enhancement on a renal-mass protocol means not solid — follow the Bosniak rules for cystic lesions.
The classic misread
- A hyperdense cyst on a nephrographic-only study mistaken for a solid mass — always need an unenhanced series.