Nephrogenic rests and nephroblastomatosis: literature review and clinical reports

Nephrogenic rests and nephroblastomatosis describe persistence of embryonic renal parenchyma (metanephric blastema) beyond 36 weeks of gestation, when nephrogenesis is normally complete. This persistent metanephric blastema may transform into the Wilms tumor, and are detected in 30–40 % of unilateral nephroblstoma and nearly 100 % in bilateral cases. The risk of Wilms tumour is increased in any type of nephrogenic rests/nephroblastomatosis but it is higher in infants and in patients with intralobar nephrogenic rests. We cite below several studies described different types of nephrogenic rests, their connection with nephroblastoma development and the details of diagnostic. We refer to clinical examples, in that regard. Two cases are presented: bilateral diffuse hyperplastic perilobar nephroblastomatosis in one child and an infant with combination of perilobar nephrogenic rests in one kidney and Wilms tumour in the other kidney.