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.
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My 4 year old son has a posterior fossa arachnoid cyst. He has global developmental delay, didn't walk until almost 2 and qualifies for pediatric therapies (pt, ot, speech) across the board. He has muscular problems and has now been found to suffer focal seizures. Problem is that I can't find a neurologist that believes this to be the cause of my sons problems. Do you know of any pediatric neurologists/neurosurgeons we could turn to? Thanks in advance.
August 27, 2009 - 11:23amThis Comment
I have a 3 year old boy who was diagnosed with an Arachnoid Cyst which was located in the Cerebellum when he was 2 1/2 years old. My son presented with global delays since he was approximately 1. The Cyst put enough pressure to shift the midline of his brain and cause mass effect on the pons and brainstem. He had craniotomy for fenestration and the surgeon, whom we are very happy with, was only able to remove less then 10%. Currently 6 months post op. my son still has a cyst approx. 4 cm and but as of our latest MRS taken a couple of months ago, the fluid is communicating and he has shown great progress in speach and motors. He still has some fine motor difficulties but nothing major. I still cannot help the constant fear of something going wrong and having to end up at Johns Hopkins again. I would really love to meet some families with children with the same type of cyst in the same location to exchange notes. I am also interested in long term stories of children who underwent fenestration of a cyst located in the cerebellum. Is there a group I can join? [email protected].
July 3, 2011 - 7:23pmThis Comment
Hi,
I was wondering what I can possibly expect for my daughter..
May 19, 2011 - 1:30pmI'm 22 weeks pregnant and through ultrasound the radiologist saw a potential posterior fossa arachnoidal cyst. It's only 1.8cm at the moment but I will be going for more ultrasounds to keep an eye on it. I was just wondering what this could be mean for her later on if it does grow.
I thought I would reply to this and see what it's like for your son and what I can maybe expect..
This Comment
Hi,
I was wondering what I can possibly expect for my daughter..
May 19, 2011 - 1:30pmI'm 22 weeks pregnant and through ultrasound the radiologist saw a potential posterior fossa arachnoidal cyst. It's only 1.8cm at the moment but I will be going for more ultrasounds to keep an eye on it. I was just wondering what this could be mean for her later on if it does grow.
I thought I would reply to this and see what it's like for your son and what I can maybe expect..
This Comment
Our 7 year old was diagnosed with a Arac-cyst on his left temporal lobe... he was having seizures at night for a year before anyone would believe us. Were now being seen by Duke, NC 919-668-4000... Dr. Galentine. He is on meds to control the seizures. I just wonder, if he's had this from birth like they say... then for it to start causing problems; it must be growing right? I hear this kind of cyst causes no problems... well guess what... we have a major problem when our son can't even go to school. Hope this helps!
September 26, 2009 - 8:01amThis Comment
Hi,
I always hate to hear of anyone with a brain cyst, but hearing that a child is suffering with a cyst is really hard to hear. Not that I am an expert by any means, but I have learned over the years that any cyst can cause problems; it just depends on the individual situation; where it is, ho big it is, etc. I think because many cysts in many different situations do not cause problems for a lot of people, doctors think that yours shouldn't be either. The cyst should always be monitored, I think; keeping track of size, growth rate, and what it is putting pressure on. And I agree, if your son cannot go to school, that is a big problem.
I hope you can get to the bottom the situation and good luck. Keep us posted.
March 30, 2010 - 4:41pmMaria
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Just wanted to let you know your not alone in NC 11/17 my 13 year old son had a mri the results came back as a arachnoid cyst of the posterior fossa we were sent to Brenners 11/23 where we were told we don't think his symptons pertain to the cyst in the back of his brain. Note the person who first read the MRI stated he had Dandy Walker which is awful and we've had a really rough past week. But more about the dr stated my son would have to have surgrey but he wanted him back in 3 months for anothe MRI to see if the cyst has grew and if there is more cerebrospinal fluid on the brain..per his words he's had this for at least 8 years I don't see that 3-6 more months will hurt anything..Note the only reason he knew the timeline was due to my sons pass out spells & black outs. This consultation alone bothered mr to no means I have researched hours beyond hours on this condition as well contacted Duke because I want a 2nd opinion I just can't live without one when it comes to my sons life. I finally got the call yesterday evenin with the size of the cyst 2inX3in (5.1cmX7.8cm) this is a nice size mass which we were told it wasn't big at all. Okay I'd like for these dr's that continue to turn there head to this serious disease to walk aeound with a cyst in the back of there brain that size or larger or any size for that matter..as well walk aeound with all these sypmtoms that my son is walkin around with, or you or your loved one...I'm thinking it would be took serious then. Today Duke called my son has a appt with Dr Grant at Duke 12/31 he was highly recomended by the office of Allen Freedman who performed Ted Kennedys surgrey. I feel like maybe I'm getting somewhere now...My sons issues came and went over the years until he had head trauma a little over a month ago...they are so bad now and new ones comin by the day...please advise the size of your childs cyst. I will keep you and your family in my prayers.
November 25, 2009 - 2:14pmThis Comment
(I'm sorry, I know I just responded to the latter post with this same comment, I meant it to be a response to you.)
My daughter was diagnosed with a posterior fossa arachnoid cyst at age 4 months. It was causing hydrocephalus, which is how it was discovered. She was also originally diagnosed with Dandy Walker Syndrome, but after closer inspection by her neurosurgeon and the radiologist, it was determined to be just a large arachnoid cyst. It was compressing her brain stem and her cerebellum. We live in Rhode Island and she was treated at Hasbro Children's Hospital in Providence. Her neurosurgeon is Dr. Petra Kinge. She is the most amazing woman and we couldn't have asked for a better doctor. Everything for us moved very fast because the hydrocephalus needed to be treated. She had a craniotomy to fenestrate the cyst one week after it was discovered. The MRI the next day showed her brain stem and cerebellum to already be back to their normal shape. She is almost a year old now, and has been doing exceptionally well. She is almost walking, and is developing right on track. She will continue to have MRI's to make sure the cyst doesn't close up again, and is now also seeing a neurologist to monitor her development. Just wanted to share a story of hope.
April 15, 2011 - 9:34amDr. Klinge isn't only a pediatric neurosurgeon, but her speciality is hydrocephalus.
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In reading this, I feel as though I am reading about myself. This seems to be a typical response with neurosurgeons that these cyst do not "normally" cause ymptoms. Well, to me, normally means that they do not always, but "can" cause them. And I heard the exact same excuse for a long, long time as I continually went downhill. I had to keep searching for a doctor who would believe me, as well as understand what these cysts are capable of. This was Dr. Robert Spetzler in Phoenix. I just had moved to Albuquerque, NM so he was my neurosurgeon of choice out at Barrow's neurological Center. He told me if I continued to let it grow, I was headed for seizures and possibly death. So thank God for him. I now live in Greensboro, NC and go to Duke as my follow-up care. Dr. Allan Freidman is my neurosurgeon there too. He is amazing. So kind, and so thoughtful...and he listens. Good luck with your endeavors. I would be interested to know what course of action is taken. Your family will be in my thoughts and prayers.
January 14, 2010 - 11:25amThis Comment
My daughter was diagnosed with a posterior fossa arachnoid cyst at age 4 months. It was causing hydrocephalus, which is how it was discovered. She was also originally diagnosed with Dandy Walker Syndrome, but after closer inspection by her neurosurgeon and the radiologist, it was determined to be just a large arachnoid cyst. It was compressing her brain stem and her cerebellum. We live in Rhode Island and she was treated at Hasbro Children's Hospital in Providence. Her neurosurgeon is Dr. Petra Kinge. She is the most amazing woman and we couldn't have asked for a better doctor. Everything for us moved very fast because the hydrocephalus needed to be treated. She had a craniotomy to fenestrate the cyst one week after it was discovered. The MRI the next day showed her brain stem and cerebellum to already be back to their normal shape. She is almost a year old now, and has been doing exceptionally well. She is almost walking, and is developing right on track. She will continue to have MRI's to make sure the cyst doesn't close up again, and is now also seeing a neurologist to monitor her development. Just wanted to share a story of hope.
April 15, 2011 - 9:32amDr. Klinge isn't only a pediatric neurosurgeon, but her speciality is hydrocephalus.
This Comment