An arachnoid cyst is a fluid filled sac that develops primarily in the uterus during the development of the brain and skull. The arachnoid membrane of the brain splits, and the split space fills with fluid known as cerebral spinal fluid. The fluid will enter the split area, but it cannot escape at the same rate as it enters. Because of this, the cyst will grow over time. The growth rate depends on many factors, but even as it grows, more times than not, the cyst will remain asymptomatic. This means that generally, an arachnoid cyst will not cause any symptoms.
Arachnoid cysts can grow anywhere on the brain with the primary areas being the side of the brain, and the top of the brain. When a cyst forms on the back of the brain, this is called a posterior fossa arachnoid cyst. A posterior fossa arachnoid cyst can create pressure on the brain stem and the cerebellum. These are extremely vital organs of the brain and they both produce tremendous functions that are required to live.
The brain stem controls a lot of our everyday functions that we do not even think about. One thing it controls is our body temperature. It controls our diaphragm for breathing, and it is where our hunger and thirst are controlled. It is also the path in which all our nerves leave the brain and travel throughout the body. The brain stem controls our pain, it is also where the nausea center is based, and it plays a role in the regulation of our hearts.
The cerebellum; on the other hand, helps control our balance. It plays a role in the reflex of our muscles, and plays a major role in our motor skills. Both parts of the brain have their very specific tasks, and when either one is compromised, it can reek havoc on the entire body.
If treatment is needed for an arachnoid cyst, usually the first choice is a fenestration of the cyst. This means going into the brain with a wand and opening up any walls that may have formed inside the cyst. These walls trap the fluid inside the cyst. The idea of this procedure is to get all the cerebral spinal fluid flowing in and out of the cyst efficiently so that the cyst does not continue to grow. If this procedure does not work, a neurosurgeon may decide to put a shunt in. A shunt helps to keep the cyst draining and not allow fluid to build up inside. If the cyst is small enough and in a space on the brain that is not too dangerous to remove, the neurosurgeon may be able to remove it altogether.
Symptoms can show themselves in many ways; from balance problems, nausea, vomiting, headaches, even seizures. Many cysts are discovered on accident when having a scan for another reason. They can be seen on Cat Scan, but the preferred diagnostic test for a brain cyst, is an MRI.
All user-generated information on this site is the opinion of its author only and is not a substitute for medical advice or treatment for any medical conditions. Members and guests are responsible for their own posts and the potential consequences of those posts detailed in our Terms of Service.
Add a Comment280 Comments
Hello I xan definately relate. The doctor told me it was nothing, my cyst was growing so I was getting sicker and sicker. Where do you stay? State? Here is my email lorena_vrc@ hotmail.com
January 7, 2015 - 12:40pmThis Comment
I am in Bakersfield, CA. As I am typing, I have been feeling kind of dizzy and have not been able to sleep. The problem is that earlier this year I was diagnosed with vertigo. The problem I have with some of these symptoms is that I get confused thinking it is one thing (vertigo) when it could be something else. I am waiting for my insurance to approve another specialist. I guess i just have to be diligent and ask a lot of questions. We will see.
Thank You!
January 8, 2015 - 5:48pmThis Comment
The doctor that did my surgery is in Los Angeles. I live in Florida but i had to get the help I needed . dont give up, do you know how big is your cyst?
January 8, 2015 - 7:06pmThis Comment
Hi, could you please let me know of the doctor that did your surgery. I was just diagnosed with an arachnoidal cyst in my posterior fossa 4cm and am freaking out that it is starting to effect my spine.
How did you surgery go btw?
Thank you very much
March 19, 2015 - 9:54pmThis Comment
what dr did you go to in LA?
January 26, 2015 - 12:10pmThis Comment
Dr. Shahinian skullbaseinstitute.com and you are not alone we are all here for each other. Thank you Maria for creating this!
January 30, 2015 - 2:13pmThis Comment
The report stated 3cm in thickness. Oh and I also have sphenoid sinus disease. I assume that the two things (both in my head) are coming together to make me feel worse. On top of everything, I am under a lot of stress (financial).
January 12, 2015 - 5:02pmThis Comment
Hello,
December 9, 2014 - 7:58amMy little boy is five and only last week they found an AC in my sons cerebellum posterior fossa . I have been told its huge 7cm – 6.5 by 6.5. Looking at the MRI snaps its totally confronting as it takes up most of the space where his cerebellum should be and its pushed his brain up and is impacting on his brain stem. He was admitted into hospital after the finding for a few days while we spoke with more neurologists and neurosurgeons. We are meeting with our Neurologist on the 22nd December and then the surgeons in about a month. They are talking surgery early next year but not completely sure . My son has always had developmental delays and they are thinking that this could be the cause. I wonder how many have had surgery and if you had the AC in that part of the brain. I want it gone but I wonder what will happen to the rest of the brain when it will leave a massive void in the cerebellum. I’m thankful for finding this group and hopefully it will make me less stressed about it all!! Thanks
This Comment
Hi Amanda,
January 3, 2015 - 8:04pmI have an arachomoid cyst in the posterior fossa. I had surgery but it grew back, i had a lot of crazy symptoms, but most of them went away after sugery. I can give you the name of the doctor that perform my surgery. He is an amazing doctor and has been feature in many Tv and medical information shows.
This Comment
Can I have the name of your doctor please!
August 7, 2015 - 8:00amThis Comment