Abstract

In contrast to the nodular renal blastema which is defined by nests of primitive metanephric cells after 36 weeks of gestation, the nephroblastomatosis is characterized by neoplastic proliferation of the primitive cells. This lesion is presumed to be closely related to the development of Wilms' tumor. We report a case of bilateral nephroblastomatosis associated with Wilms' tumor in a child. This 4 1/2 year-old girl was admitted because of a 10 cm-sized round mass in the right kidney, and smaller nodules in the left kidney and the lung. After three cycles of chemotherapy and subsequent disappearance of the nodules in the left kidney and lung, she underwent a right nephrectomy and a wedge resection of the left kidney. A round Wilms' tumor mass was seen in the lower pole of the right kidney. Remaining right renal cortex showed multiple, slightly depressed gray-white nodules associated with multiple samll cysts. They were comprised of multifocal subcapsular nests of primitive nephrogenic cells with focal tubular or glomerular differentiation. They resembled fetal renal tissue. In the left kidney, similar nests of primitive cells were also noted. These lesions were interpreted as multifocal perilobar type of nephroblastomatosis.

• Keywords: Nephroblastomatosis;Wims' tumor;Kidney;