A nephroblastoma, or Wilms tumor, is the most common renal malignancy in children, typically occurring before age 5. It arises from embryonic kidney tissue and may be associated with congenital syndromes such as Beckwith-Wiedemann syndrome. On ultrasound, a nephroblastoma appears as a large, solid, partially echogenic mass that may distort the kidney’s shape and extend beyond the renal capsule into the perirenal fat or vena cava. The mass may contain areas of hemorrhage or necrosis making it heterogeneous. Given the aggressive nature of this tumor, prompt diagnosis and staging are critical, with imaging used to assess for contralateral kidney involvement and vascular invasion.
Sonography Term