Medullary Sponge Kidney: Macroscopic Features
Section Editor: Dharam M. Ramnani, MD
Virginia Urology, Richmond, VA, USA
Image Description
Macroscopic Features: In medullary sponge kidney (MSK), the kidneys are normal in size and function. The cut surface shows multiple small cysts in medullary pyramids and papillae. The cysts are present in all pyramids in both kidneys; however, in some cases they may be confined to one or two pyramids or only in one kidney. MSK is often associated with nephrolithiasis. The stones are usually composed of calcium oxalate and/or calcium phosphate and often found incidentally on radiographic evaluation of patients with unexplained hematuria or urinary tract infection.