A 4-year-old child presents with intermittent abdominal pain and a large, smooth, non-tender right abdominal mass that does not cross the midline. Urinalysis shows microscopic hematuria. Ultrasound shows a solid intrarenal mass. Which of the following staging criteria in Wilms tumor (nephroblastoma) would indicate Stage III disease according to the COG/NWTSG staging system?
- A Tumor confined to the kidney, completely resected, with intact renal capsule
- B Tumor extending beyond the kidney with complete surgical resection
- C Hematogenous metastases to lungs
- D Residual tumor confined to the abdomen (positive margins, positive lymph nodes, peritoneal implants, or pre/intraoperative tumor spillage) ✓
Explanation
In the COG/NWTSG Wilms tumor staging: Stage I is confined to kidney, fully resected, capsule intact; Stage II extends beyond kidney (through capsule, perinephric fat, or renal sinus) but fully resected; Stage III has residual nonhematogenous tumor confined to the abdomen — this includes positive resection margins, involved abdominal lymph nodes, peritoneal surface implants, incomplete resection, or biopsy/tumor spillage before or during surgery; Stage IV has hematogenous metastases (lung, liver, bone, brain); Stage V is bilateral renal involvement. Recognizing Stage III is critical because these children receive more intensive chemotherapy (actinomycin D + vincristine + doxorubicin) plus whole-abdominal radiation.
Reference: Ghai Essential Pediatrics, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.