Renal Dysplasia: Microscopic Features
Section Editor: Dharam M. Ramnani, MD
Virginia Urology, Richmond, VA, USA
Image Description
Multicystic dysplastic kidney is composed of disorganized immature renal parenchyma. There are variably-sized cysts lined by cuboidal or flattened epithelium. The intervening stroma contains sparse numbers of primitive tubules and ducts lined by undifferentiated cells and surrounded by a collarette of smooth muscle. In addition, the stroma has thick-walled vessels, lymphatics, peripheral nerves and metaplastic cartilage (30% of cases). Metaplastic cartilage is not required for the diagnosis of multicystic renal dysplasia. However, collars of poorly-differentiated smooth muscle cells around primitive ducts are always present and are required for the diagnosis.