A large renal mass in a young child that arises from the kidney (claw sign), displaces rather than encases vessels, and may extend into the renal vein and IVC — report the contralateral kidney, the venous extent and the lungs.
Orient first
- Peak age 3–4 years; bilateral in a minority (syndromes, nephroblastomatosis).
- Wilms displaces vessels and crosses the midline less; neuroblastoma encases vessels, calcifies and lifts the aorta.
- SIOP (pre-operative chemotherapy) and COG (upfront surgery) pathways differ (verify which applies).
Acquire the study
- Curvilinear probe; colour Doppler of the renal vein and IVC.
The manoeuvre
- Mass arising from the kidney: claw of normal parenchyma around it.
- Size in cm in three planes; heterogeneity.
- Renal vein and IVC: tumour thrombus and its upper extent on colour Doppler.
- Contralateral kidney: a second lesion.
What confirms it
- A renal-origin mass with typical features; histology after chemotherapy or surgery.
What licenses you to exclude it
- Adrenal origin, vessel encasement and calcification favour neuroblastoma.
The classic misread
- An adrenal neuroblastoma indenting the kidney mistaken for a renal mass.