Kidney (renal) cysts: what your scan report really means.
A cyst on a kidney ultrasound report sounds alarming — but the vast majority are simple, harmless findings. Here is how to read yours calmly, and when treatment is actually needed.
What is a kidney cyst?
A kidney (renal) cyst is a round, fluid-filled sac that forms in or on the kidney. They are remarkably common — many adults over 50 have one without ever knowing. Most are simple cysts: thin-walled, filled with clear fluid, and completely harmless.
Cysts are usually discovered by chance — on an ultrasound or CT scan done for another reason, such as a health check or abdominal pain. The important step after any report is having the scan read properly once, so the cyst can be confidently classed as simple or looked at more closely.
Usually silent — but not always.
- Most simple cysts cause no symptoms at all
- A large cyst can cause a dull ache in the side or back
- Rarely, a cyst can bleed or get infected — causing pain, fever or blood in urine
- Very rarely, a cyst pressing on the kidney can contribute to high blood pressure
Found a cyst on your report? Don't panic — but don't ignore it either. One consultation to read the scan properly tells you whether yours needs nothing at all or a closer look.
How cysts are evaluated.
- Ultrasound — usually the first scan; confidently identifies most simple cysts
- CT or MRI — used when a cyst looks anything other than completely simple
- Bosniak grading — radiologists grade cysts from I (clearly simple) to IV based on their wall, internal divisions and contents. Simple grades need only reassurance, grade 2F cysts require follow-up scans, while grade 3 and 4 cysts may require further evaluation to rule out malignancy
When treatment is needed — and when it isn't.
- Observation — the right answer for most simple cysts; sometimes with a follow-up scan after a year
- Laparoscopic removal (deroofing) — keyhole surgery to remove the cyst wall when a cyst is very large, keeps causing symptoms, or needs to be examined thoroughly
The choice depends entirely on what the scans show and whether the cyst is causing symptoms — most people leave the consultation with reassurance rather than a procedure.
Consultant Urologist, Andrologist and Robotic Surgeon. He evaluates kidney cysts and performs laparoscopic cyst surgery at MEDICOVER Hospitals, Hitec City and LUX Hospitals, Gachibowli.
View full doctor profile →Frequently asked questions.
Is a kidney cyst cancer?
The vast majority of kidney cysts are simple cysts — harmless fluid-filled sacs that are not cancer and do not turn into cancer. Scans grade cysts by their appearance (the Bosniak system); cysts graded 3 or 4 may require further evaluation to rule out malignancy.
Does a kidney cyst need treatment?
Most kidney cysts need no treatment at all — just one proper reading of the scan, and occasionally a follow-up scan. Treatment is considered when a cyst is large, causing pain or other symptoms, or shows complex features.
Can a kidney cyst cause pain?
Simple cysts are usually silent and are found by chance on an ultrasound done for another reason. A large cyst can sometimes cause a dull ache in the side or back, and rarely a cyst can bleed or get infected.
Will a kidney cyst affect my kidney function?
A simple kidney cyst does not affect kidney function. Only rare inherited conditions with hundreds of cysts (polycystic kidney disease) affect function — a very different situation from a simple cyst.
Get your scan report read properly.
Request an appointment with Dr. Sreeniketh Reddy at MEDICOVER Hospitals, Hitec City or LUX Hospitals, Gachibowli.