Bilateral renal dysplasia with features of nephroblastomatosis.

We report a case of bilateral renal dysplasia with "cystic nephroblastomatosis" in a 29-week-old white female infant. The patient presented with bulging flanks, anuria, and respiratory distress. She survived for 1 1/2 days. Both kidneys were markedly enlarged by a diffuse cystic malformation. Microscopically, there was no demarcation between cortex and medulla. Numerous cysts and partially differentiated metanephric blastema cells were seen throughout the cortex and medulla. In addition, dysplastic tissues including cartilage occurred in the medulla. No evidence of Wilm's tumor was found. To our knowledge, this unique form of renal pathology has not been previously reported.