Nonvisualization of the intravenous pyelogram--a poor prognostic sign in Wilms' tumor?

In a series of 49 consecutive cases of Wilms' tumor from a single institution, there was a 20% incidence of nonvisualization on the initial intravenous pyelogram. Even though nonvisualization was secondary to either gross or microscopic invasion of the renal vein or renal pelvis, this did not forecast a grim progosis. Seven of the nine patients with nonvisualization are presently alive and tumor-free at least 5 yr after resection. The only two deaths in this particular group were unrelated to the Wilms' tumor.