Radiologic Evaluation of Small Renal Masses (I): Pretreatment Management

Table 1

Staging system for renal carcinoma and CT criteria.

Tumour position	Robson	TNM	CT findings
Confined within	I		Soft-tissue mass enhances
renal capsule			less than normal renal
Small (<7 cm)		T1	parenchyma; central
Large (≥7 cm)		T2	necrosis in large RCC.
	II	T3a	Perinephric stranding;
Spread to perinephric fat			Perinephric collateral vessels;
			Soft-tissue mass in perinephric space
Venous thrombus	III A
Renal vein only		T3b	Low-attenuation filling defect vein;
IVC infradiaphragmatic		T3c	Direct continuity of thrombus with primary mass;
IVC supradiaphragmatic		T4b	Enhanced thrombus
Regional lymph	III B	N1-N3	Lymph nodes 1 cm in diameter or larger
node metastases
Direct invasion of adjacent organs	IV A	T4a	Obliteration of normal soft-tissues planes between tumor and adjacent organs
Distant metastases		M1	Metastases enhance with IV contrast material;
			Hepatic metastases best in arterial phase

IV: intravenous, IVC: inferior vena cava.