Kidney cysts are fluid-filled sacs that can form inside or on the kidneys. Learn the difference between simple and complex cysts, symptoms, testing, and treatment in easy-to-understand language.Â
Kidney cysts are small, round sacs filled with fluid that grow inside or on the kidneys.
They are very common, especially as people get older.
Most kidney cysts are:
Non-cancerous
Harmless
Found by accident during imaging tests
Many people never even know they have them.
The most common type
Usually harmless
Thin, smooth walls
Filled with clear fluid
Rarely cause problems
These may have:
Thick walls
Irregular shapes
Solid areas
Calcifications
Complex cysts sometimes need closer monitoring because a small number can be cancerous.
In most cases, the exact cause is unknown.
Simple cysts often develop as part of normal aging.
Other possible causes include:
Blockages in tiny kidney tubules
Weak spots in kidney tissue
Certain inherited conditions
Having one or two simple cysts is usually not a sign of kidney disease.
Most kidney cysts cause no symptoms at all.
If symptoms do occur, they may include:
Dull pain in the side or back
Feeling of fullness
Blood in the urine
Fever (if a cyst becomes infected)
High blood pressure
Symptoms usually happen only if a cyst becomes large or complicated.
Kidney cysts are usually found with imaging tests.
Kidney Ultrasound
Most common way to find cysts
Can easily show simple cysts
CT Scan or MRI
Used to look more closely at complex cysts
These tests help check:
Overall kidney function
Signs of infection
Other kidney problems
Most simple cysts need:
No treatment at all
Doctors usually just monitor them if needed.
The cyst is very large
It causes pain
It gets infected
It blocks urine flow
Possible treatments include:
Draining the cyst
Injecting medicine to shrink it
Rarely, surgery
In most people – no.
Simple kidney cysts are usually harmless.
However, cysts can be more serious if they are:
Complex in appearance
Growing over time
Causing symptoms
Part of a genetic condition like PKD
Your doctor will decide if further testing is needed.
Talk to a doctor if you have:
Ongoing side or back pain
Blood in your urine
Fever with kidney-area pain
A cyst that is growing
Abnormal imaging results
Most kidney cysts are simple, harmless, and never cause problems.
Only a small number need treatment or close follow-up.Â