Medullary Sponge Kidney

Pathology

Congenital defect
Manifest symptomatically in third or fourth decade
Multiple cystic dilatation of the collecting ducts in the medulla, diameters ranging from 1 to 5 mm.
Not all papillae are equally involved
Bilateral in 70% of cases
Calculi are frequently found in the dilated collecting ducts

Imaging strategy

Patients present with renal stones or infection or hematuria or discovered incidentally
Most commonly diagnosed by intravenous pyelogram.
- In IVP you can see leniar striations radiating into renal papillae or small cystic collections of contrast in the distal ducts
- You may see tiny calcifications in pyramids adjacent to fornices
In the modern days IVP is not done any more.
About 60% have renal stones
Plain film and CT abdomen are the imaging procedures of choice for investigation of patients suspected to have renal stones.
In CT you may see bilateral renal calcifications in the cortico medullary junction