Autosomal Recessive Polycystic Kidney: Microscopic Features
Section Editor: Dharam M. Ramnani, MD
Virginia Urology, Richmond, VA, USA
Image Description
Autosomal recessive polycystic kidney disease (ARPKD) - Microscopic Features: There is fusiform dilation of the collecting tubules. The long axis of the dilated tubules is oriented at right angles to the renal cortical surface, as nicely seen in this image. This creates the radiating arrays from medulla to the cortex seen grossly. The cyst lining consists of uniform cuboidal epithelium. The thin septa between the cysts contain normal glomeruli and tubules and scant fibromyxoid stroma. Fibrosis and chronic inflammation are generally absent from the interstitium. Cysts in the medulla tend to be somewhat rounded.
In less severely affected cases, the kidneys have a variable appearance. Renal enlargement is not as impressive and cysts are fewer in number. Fusiform elongation and dilation of renal tubules is always present in the medulla. In long-standing cases, there is interstitial fibrosis and glomerulosclerosis, which can resemble autosomal dominant polycystic kidney disease (ADPKD). However, all forms of ARPKD will show liver pathology (irregularly branching and anastomosing bile ductules and increased portal fibrosis) that helps its distinction from infantile ADPKD.
In less severely affected cases, the kidneys have a variable appearance. Renal enlargement is not as impressive and cysts are fewer in number. Fusiform elongation and dilation of renal tubules is always present in the medulla. In long-standing cases, there is interstitial fibrosis and glomerulosclerosis, which can resemble autosomal dominant polycystic kidney disease (ADPKD). However, all forms of ARPKD will show liver pathology (irregularly branching and anastomosing bile ductules and increased portal fibrosis) that helps its distinction from infantile ADPKD.