Polycystic kidneys. Coloured magnetic resonance imaging (MRI) scan of the abdomen of a patient with polycystic kidneys. The majority of the tissue of the kidneys has been replaced by cysts (yellow). Polycystic kidney disease is one of the most common causes of chronic kidney failure in adults. It is an inherited condition that may occur at any age. Treatment is of the kidney failure, either with dialysis or transplantation.