Nephroblastomatosis and Wilms' tumor. Clinical experience and management of seven patients.

Nephroblastomatosis is an uncommon abnormality believed to represent the persistence of embryonal renal tissue. Its association with simultaneous or eventual Wilms' tumor has led to the speculation that it is a premalignant lesion. The accumulated clinical experience with this process and its progression to Wilms' tumor in three of seven individuals is discussed. It is concluded that conservative tissue sparing surgery, chemotherapy, and ultrasonographic follow-up are the approaches most appropriate for the management of these difficult patients.