What it means
A liver cyst is a pocket of fluid with a very thin wall. Simple cysts are thought to form before birth from tiny bile ducts that never joined up, and they grow slowly, if at all. On ultrasound a simple cyst looks black (anechoic) with a thin, smooth wall. On CT it has the density of water. On MRI it is bright on T2 images and does not take up contrast.
When it matters
Simple liver cysts are found in many adults and almost never cause problems. Very large ones can press on nearby organs. A cyst with thick walls, inner walls (septations) or solid parts that take up contrast is called complex. It needs a closer look, often with MRI. Large numbers of cysts can point to an inherited condition, such as polycystic liver or kidney disease.
Questions to ask your doctor
- Does the cyst look simple, or does it have any complex features?
- Does this cyst need any follow-up scan at all?
- Is the cyst large enough to cause any of my symptoms?
