Cystic nephroma, cystic partially differentiated nephroblastoma and cystic Wilms' tumor in children: A spectrum with therapeutic dilemmas

Background: Cystic renal tumors are a diagnostic and therapeutic challenge. Cystic nephroma (CN), cystic partially differentiated nephroblastoma (CPDN) and cystic Wilms' tumor (CWT) are a spectrum with CN at the benign end, CWT at the malignant end and CPDN in the intermediate position. CN and stage 1 CPDN are often treated with surgery alone. International Society of Pediatric Oncology (SIOP) protocols for Wilms' tumor (WT) advocate preoperative chemotherapy, which may be unnecessary and potentially harmful in CN and in stage 1 CPDN. There are difficulties in differentiating the three types using imaging techniques. Therefore, controversies exist regarding the optimal treatment. Methods: We describe 6 children, who each had a postoperative diagnosis of CN, CPDN or CWT, and we retrospectively evaluate the treatment strategies. Results: The three types cannot be differentiated using imaging techniques, although the presence of solid components in the tumor is indicative of WT. Conclusions: Surgery as first-line therapy should be seriously considered in children who have a cystic renal tumor, but further collaborative studies are needed since the distinction line between CPDN and CWT is not always clear.