Alteration of wilms' tumor staging by cytologic detection of malignant cells in chylous ascites

Accurate staging as per National Wilms' Tumor Study (NWTS) criteria is essential for therapy of Wilms' tumor. We report a unique case of a 9‐mo‐old white male in whom the diagnosis based upon clinical, radiological, surgical, and initial histopathologic findings was Stage I Wilms' tumor without regard to a positive cytologic examination of a small amount (5 ml) of chylous ascitic fluid obtained intraoperatively. This problem was clarified later at the NWTS panel review when the deeper recuts of a renal hilar lymph node revealed a single cluster of Wilms' tumor cells in capsular sinus, resulting in upstaging of tumor to Stage III. the significance of these findings in relation to staging will be discussed. © 1995 Willey‐ Liss, Inc.