Polycystic kidney disease. Colour scanning electron micrograph (SEM) of a kidney affected by polycystic kidney disease (PKD). The large oval shaped object is a fluid filled cyst whilst the smaller dark objects are blood vessels. PKD is characterised by the growth of numerous cysts in the kidneys. Eventually they will cause the kidneys to fail (end-stage renal disease) leading to dialysis or transplantation. There are three types of PKD: autosomal dominant and recessive - which are inherited; and acquired cystic kidney disease - which develops in association with long- term kidney problems.