Which pediatric renal tumor is described as an echogenic malignant solid mass?

• A. Wilms tumor
• B. Renal agenesis
• C. Polycystic kidney disease
• D. Ureterocele

Answer: (A)

Wilms tumor is the classic pediatric renal tumor that presents on ultrasound as a solid malignant mass within the kidney, often described as echogenic. The lesion is intrarenal and tends to distort the normal renal architecture, sometimes displacing vessels and the renal contour. This solid, malignant intrarenal mass distinguishes it from other pediatric renal conditions.

Renal agenesis would show an absent kidney rather than a mass. Polycystic kidney disease shows enlarged kidneys with multiple cysts and a predominantly cystic-appearing texture rather than a solid mass. A ureterocele is a dilated distal ureter that protrudes into the bladder, not a solid renal mass.