What it means
The pineal gland is a small gland near the center of the brain that makes melatonin, a hormone involved in sleep. A pineal cyst is a pocket of fluid inside it, usually under 10 mm. On MRI it looks round and smooth, often with a thin bright rim after contrast. Cysts like this are a common chance finding on brain MRI.
When it matters
Typical pineal cysts rarely grow or cause symptoms, and they usually need no follow-up scans. Doctors look more closely if the cyst is large, has thick or uneven walls or solid parts, or presses on nearby structures. Very rarely, a large cyst blocks the flow of brain fluid and causes headaches or trouble moving the eyes. Comparing with older scans can help.
Questions to ask your doctor
- Does the cyst look typical, or does it have any unusual features?
- Is it large enough to press on anything nearby?
- Do I need another scan, or is this a one-time finding?
