MRI Report

I recieved a copy of my son's MRI report, the findings are Prominent cisterna magna versus posterior fossa arachnoid cyst.  What in the world does this mean in "mom" language??  My son's doctor is sending us to Riley's in month, and told me not to worry.  I'm a mom that's my job, but would like more information.
Thank you for any insight that can be given,
Krista

[Godofredo MD]

Hi.

The cisterna magna is a space between the cerebellum and the medulla which allows for drainage of cerebrospinal fluid (CSF).

Arachnoid cysts are sacs filled with CSF located between the arachnoid membrane and the brain or spinal cord. They can be primary or secondary depending on their etiology. Arachnoid cysts only produce symptoms when they become large enough to put pressure on adjacent brain structures. Symptoms of brain arachnoid cysts may include headache, nausea and vomiting, seizures, hearing and visual disturbances, vertigo, and difficulties with balance and walking.

Hope this helps.

[Abhijeet Deshmukh, MD]

Hello.

In other words, the MRI has found sn increased "space" in the back side of the brain, which is taking the place of the brain tissue. Since it's in the posterior fossa ( rear one third of the skull), there can be issues with circulation of the CSF (cerebro spinal fluid) and imbalance.

Regards