Wilms Tumour (Nephroblastoma)

Wilms tumour, also called nephroblastoma, is the most common paediatric renal cancer. It develops when embryonic kidney precursor cells, including nephrogenic rests, undergo malignant transformation. The growing tumour expands within or around the kidney, so a child may develop an abdominal mass before appearing acutely ill. The classic finding is a firm, usually painless abdominal mass or increasing abdominal girth. The mass may cause haematuria, abdominal discomfort, vomiting, constipation, or reduced appetite through local pressure. Renal involvement can also produce hypertension through altered renal perfusion and renin release. A high blood pressure reading in a child with an abdominal mass is therefore a disease clue, not simply a response to anxiety. The tumour can rupture with forceful palpation or abdominal trauma, causing haemorrhage and spilling tumour cells into the abdomen. A child with a suspected renal mass should not have the abdomen repeatedly or deeply palpated. Gentle assessment, vital signs, and prompt communication are safer than trying to define the mass by examination. Several conditions can produce a paediatric abdominal mass, including neuroblastoma, hydronephrosis, lymphoma, and constipation. The mass alone...