A pathological study of nephroblastoma with congenital aniridia.

A pathological study was conducted on four patients with nephroblastoma associated with aniridia. The age at diagnosis. was one year in three cases and 4 years in one case. Chromosomal analysis was performed in three cases, and showed 11p13 deletion in all. Each nephroblastoma consisted of metanephric blastemal, epithelial, and mesenchymal cells. All the tumors were centrilobar, and in one case an additional polypoid tumor grew into the renal pelvis. Histological examination showed conspicuous heterotopic cells, such as striated muscle and adipose tissue. Striated muscle was seen in all four cases, while both adipose tissue and smooth muscle were seen in two cases. Squamous epithelium was present in two cases. A literature survey revealed a high incidence of bilateral occurrence in cases of nephroblastoma associated with aniridia. Intralobar nephroblastomatosis was observed in all four cases, and it is proposed that this is the precursor lesion of nephroblastoma associated with aniridia.