Brain Cysts - Identification?

Hi - my daughter was recently dx'ed (after a grandmal seizure) with a cysts on the brain.  The Neurosurgeon says it is in an "easy" place to remove it.. here's the concern...  He has not identified the type of cyst (arachnoid, etc) and says they won't know until they have done surgery.  They did do a head CT and an MRI and an EEG (which shows a good possibiilty that the cysts is in the same area as where the abnormal signal are coming from) it isn't looking like cancer but no one has identified and named the cyst.  Should the cyst be fully identified before surgery?  Or perhaps the question is CAN it be identified before surgery or is it common for the neurosurgeon to not know what type of cyst he is dealing with until surgery.. And wouldn't the identification help with the understanding of whether surgery is necessarybecause the neurologist believes that my daughter "can life out her life with medications and have a good chance of not having any more seizures".. so of course we are a bit confussed by what to do.. surgery or medications..  Thanks for any info...

[Christopher R Newey, DO]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.

Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.

Several types of cysts occur in the brain. Not all cysts are dangerous, and not all cysts need to be removed.

One type of cyst is the arachnoid cyst. Our brain is covered by a layer of tissue called the meninges. This layer of tissue is made up of 3 layers, one of which is called the arachnoid. An arachnoid cyst is a developmental cyst that occurs in the arachnoid membrane. They can occur anywhere within the central nervous system (brain or spinal cord) but are most commonly found in the brain. Sometimes, more than one can be found in the same person.

The exact cause of arachnoid cysts is unclear, but the majority are thought to be developmental: occur as a human develops, present since birth. Secondary arachnoid cysts, cysts occurring from a particular reason, are much less common. They can occur after epidural anesthesia, overdrainage of CSF due to specific draining systems placed for various reasons, or spinal injury or surgery.

The symptoms of arachnoid cysts vary depending on their size and location. Most are present since birth. Most people don't cause any symptoms or problems. In most people, they are discovered incidentally. Care should be taken when attributing the patient's symptoms to the presence of the cyst. Symptoms that may be caused by arachnoid cysts (depending on their location and size) may include seizures, psychiatric problems, and headaches. Complications from cysts including bleeding (subdural bleeding), but this is not common.

Some cysts resolve spontaneously, but most arachnoid cysts remain the same size or increase in size only slightly in adulthood, and others fluctuate over time.

Asymptomatic arachnoid cysts identified incidentally probably should be left alone. In cases with epilepsy where the cyst appears to be under pressure, surgery should be considered, although it may not result in seizure control. The decision to operate is usually taken by a neurologist and/or neurosurgeon. If a cyst is determined to be causing symptoms or pressure in the head, it may be removed. I can not discuss with you the details of the neurosurgical procedures as this is not my area, but the procedures can often be done endoscopically (with the assistance of a small scope) and with stereotactic guidance (a technique that allows accurate localization), minimizing the invasiveness of the procedure and the complication rate.

There are many different types of cysts. Many can be identified radiologically with the various MRI sequences and “classic” locations. However, pathological evaluation is the only way to truly know what the cyst is. For example, sometimes, tumors and other lesions in the brain such as infections and remote ischemic areas can appear as cysts.

Treating epilepsy with medication should always be given a fair trial. Only after failing several medications should surgery be performed. I highly suggest you discuss your options with your neurologist and neurosurgeon.

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.

[TheresaCatherine]

Thank you for your time and attention to this post.. Most of the information you put forth I had been aware of because of my research.. but what jumped out at me is the comment that they CAN resolve spontaneously... I had asked our neurosurgeon just that question (can it resolve without interferrence) and I was told "no".. I also asked, since she is a teenager and there was never any evidence of seizure before.. "how long will the brain continue to grow" and was told "it is probably shrinking as we speak" but she is only 16.. it didn't match up to the research I did after the seizure.. I would think that perhaps if the brain was growing that that may have been the cause of seizure as well...  anyway, again thank you - knowledge is powerful and I feel more powerful after your input.. take good care, Theresa-C