Congenital obstructive uropathy and nodular renal blastema.

The occurrence of nodular renal blastema and renal dysplasia was determined in a retrospective study of 75 cases of congenital obstructive uropathy. Nodular renal blastema was present in 3 upper pole nephrectomy specimens removed as a consequence of nonfunction owing to ectopic ureterocele; none was dysplastic. A more differentiated type of nodular renal blastema was present in 3 other total nephrectomy specimens, bilateral involvement in a case of posterior urethral valves and unilateral nodular renal blastema associated with ureteral atresia. This subset of differentiated nodular renal blastema was associated with renal dysplasia.