NCIt definition : A developmental disorder of the kidney characterized by cystic dilatation of the medullary
collecting ducts, resulting in a spongy gross appearance of the kidney. It may be
asymptomatic or complicated by hematuria, infections, or renal stones.;
Alternative definition : NICHD: A congenital renal disorder characterized by dilatation and dysplasia of the
medullary and papillary portions of the collecting ducts, usually resulting in the
formation of medullary cysts and nephrocalcinosis.;