Bilateral Wilms' Tumor With Different Responses to Preoperative Chemotherapy.

Wilms' tumor (WT) is a common type of primary renal tumor in the pediatric population that can equally affect both sides. Herein, we describe a case of bilateral Wilms' tumor (BWT) in a three-year-old male with different responses to preoperative chemotherapy in the two kidneys. The left kidney mass responded poorly to chemotherapy than the right kidney, which raised the suspicion of coexisting benign disease or congenital anomaly.