A 3-year-old boy is found to have a large, smooth, firm left renal mass discovered by his mother while bathing. Blood pressure is 118/76 mmHg. The mass does not cross the midline, and there are no skin lesions. Contrast CT shows an intrarenal mass distorting the collecting system with a small rim of functioning parenchyma around it. The most likely diagnosis is:
- A Neuroblastoma arising from the left adrenal gland
- B Wilms tumour ✓
- C Multicystic dysplastic kidney
- D Renal cell carcinoma
Correct answer: B. Wilms tumour
Explanation
An intrarenal mass that displaces and distorts the pelvicalyceal system while leaving a rim of functioning parenchyma is characteristic of Wilms tumour, the commonest renal malignancy of childhood, typically presenting at 3 to 4 years as an incidental smooth mass. Neuroblastoma is extrarenal, crosses the midline, elevates rather than invades the kidney, and more often causes hypertension and catecholamine features. Renal cell carcinoma is rare below 10 years of age.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.