Cyst: Meaning in a Radiology Report

Cyst

Also written as: cystic lesion, simple cyst, complex cyst, cystic structure

A cyst is a sac filled with fluid. Simple cysts are very common and almost always harmless; cysts with thick walls or solid parts get a closer look.

Seen on: Any scan

How it reads in a report

A 2.4 cm simple cyst in the lower pole of the left kidney (Bosniak I) requires no follow-up.

What it means

A cyst is a pocket with a thin wall and fluid inside. Cysts are very common in the kidneys, liver, ovaries, breasts and thyroid, and many people have several without knowing. A simple cyst has a smooth, thin wall and clear fluid. Sound passes straight through clear fluid, so on ultrasound it looks black. On CT and MRI it matches the look of water.

When it matters

Simple cysts are almost always harmless and usually need no follow-up. Radiologists look more closely at complex cysts, meaning ones with thick walls, inner dividing walls, debris or solid parts. Many of these are still harmless, for example a cyst that has bled, but some need a repeat scan or another test. Kidney cysts are graded with the Bosniak classification.

Questions to ask your doctor

Is my cyst simple or complex?
Does it need any follow-up, and could it cause symptoms?
If it is complex, which grading system was used and what grade is it?