Cystic disease
A cyst is an epithelium-lined sac of fluid. They are commonly found incidentally in the kidney as solitary lesions.
Cystic kidney disease is a group of conditions in which the kidney develops numerous cysts.
They can be acquired or congenital.
Acquired cysts
- Most common in patients with CKD, specifically those on dialysis for many years, probably due to hyperplasia of the residual functioning tissue.
- Usually asymptomatic, but may cause bleeding and hematuria.
- Increase the risk for RCC. Patients with multiple acquired cysts should be screened using US.
Congenital cysts
There are many causes for congenital cystic renal disease. The most prominent ones are polycystic kidney disease, nephronophthisis, and medullary cystic kidney disease.
Polycystic kidney disease
PKD is generally classified into two entities, they are they ADPKD and ARPKD (a third entity, sporadic PKD, also exists, but is extremely rare).
- ADPKD is more common, less severe, manifesting later in life, caused by a defect in the PKD1/2 gene. CKD and renal failure commonly appears in late adulthood.
- ARPKD is more rare, more severe, caused by a defect in the PKHD1 gene. Renal failure is common in childhood.
- The kidneys are enlarged; hepatic cysts are also common (with minimal impairment), intracerebral berry aneurysm