What are the features distinguising neuroblastoma from Wilms tumour?
With Wilms tumour the following apply: •calcification uncommon : 10 - 15% •displaces adjacent structures with out insinuating between them •well circumscribed •claw sign with the kidney •slightly older age group : peak 3 - 4 years of age •extension into IVC / renal vein
What is the claw sign?
The claw sign is useful in determining whether a mass arises from a solid structure or is located adjacent to it and distorts the outline. It refers to the sharp angles on either side of the mass which the surrounding normal parenchyma forms when the mass has arisen from the parenchyma, classically in the kidney. It is best observed in Wilm's tumour and adds in distinguishing from a neuroblastoma which is not solid organ derived.
Huge right sided renal derived mass, without internal calcification.
Huge displacement of liver and adjacent structures from right renal mass.
No calcification in the right sided abdominal mass. An important consideration with paediatric abdominal mass in distinguishing a Wilm's tumour from neuroblastoma.