There are two significant categories of kidney cysts, the most common type of kidney cyst is the simple kidney cyst and the complex cyst.
Cystic kidney disease relates to a wide hereditary, developmental, and acquired conditions.
Cystic kidney disease can be genetic, developmental, cysts with systemic disease association can be acquired, or malignant.
There are over 40 classifications and subtypes.
Prevalence ranges between 2.5% and 41% and increases with age.
Up to 50% of adults over the age of 50 have at least one renal cyst.
Thin non vascularized septation do not substantially increase the risk of malignancy.
It is typical for cysts to slowly enlarge at a rate between 3% and 5% annually, and the small increases in size with an otherwise stable appearance is not a cause for concern.
Simple cyst is a benign process.
Complex cyst related to a spectrum of cystic changes which may make them suspicious for a cancerous lesion of the kidney.
Kidney cysts may occur at any age.
Simple cysts increase with age.
Simple cysts more common in men, occurring in 46% of men, and 23% of women over the age of 75 years (Caglioti A).
May be associated with systemic disease.
Simple cysts not associated with pain, hypertension, or proteinuria.
Simple cysts may be associated with erythrocytosis.
Bosniak cyst classification utilizes CT criteria.
Ultrasound is generally sufficient to diagnosis simple cyst, but it may not be definitive.
MRI lacks spatial resolution of CT and ultrasound, but provides excellent contrast resolution and can provide information on hemorrhagic or proteinaceous debris within a cyst.