Infant with a renal mass on prenatal ultrasound

CT of mesoblastic nephroma, cellular subtype
Coronal CT with contrast of the abdomen (below) shows a solid mass with variable enhancement with cystic components within the right kidney. Axial CT (above) shows the cystic component of the mass extends to the midline. No claw sign is present. The left kidney is normal.

The diagnosis was mesoblastic nephroma, cellular type.