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Genetic and Rare Diseases Information Center (GARD)

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Arachnoid cysts

Other Names for this Disease
  • Arachnoid cysts, intracranial
  • Intracranial arachnoid cysts
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Your Question

My granddaughter was recently diagnosed with arachnoid cysts. Can you provide me with information about this condition? Is it genetic?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What are arachnoid cysts?

Arachnoid cysts are sacs filled with cerebrospinal fluid (CSF) that are located between the brain or spinal cord and the arachnoid membrane, one of the three membranes that cover the brain and spinal cord. Arachnoid cysts can be primary or secondary. Primary arachnoid cysts are congenital (present at birth), resulting from abnormal development of the brain and spinal cord during early pregnancy. Secondary arachnoid cysts are less common and result from head injuries, meningitis, tumors, or as a complication of brain surgery. Signs and symptoms depend on the location and size of the cyst and may include headache, nausea and vomiting, seizures, hearing and visual disturbances, vertigo, and difficulties with balance and walking. Although many affected individuals develop symptoms in the first year of life, some never develop symptoms. Whether and how to treat the condition depends on the location and size of the cyst; when treatment is recommended, it may include placing a shunt to drain the fluid; surgically removing the cyst membranes; or opening the cyst so the fluid can drain into the CSF.[1]
Last updated: 7/11/2013

What are the signs and symptoms of arachnoid cysts?

In some cases, arachnoid cysts do not cause any symptoms.[2] The location and size of the cyst in each individual determine whether symptoms occur, as well as when they might begin. Most individuals develop symptoms before age 20, and especially during the first year of life. Signs and symptoms of arachnoid cysts that are located around the brain may include headache, nausea and vomiting, seizures, hearing and visual disturbances, vertigo, and difficulties with balance and walking. Arachnoid cysts located around the spinal cord can compress the spinal cord or nerve roots and may cause symptoms such as progressive back and leg pain, and/or tingling or numbness in the legs or arms.[3][1]
Last updated: 7/11/2013

What causes arachnoid cysts?

The exact underlying cause of arachnoid cysts is unknown.[2] Primary arachnoid cysts, which are congenital (present at birth), are due to developmental abnormalities of the brain and spinal cord during the early fetal period. Secondary arachnoid cysts, which occur more rarely, are associated with head injury, hemorrhage, meningitis, tumors, or a complication of brain surgery.[4][1]
Last updated: 7/11/2013

Are arachnoid cysts inherited?

Most cases of arachnoid cysts are sporadic - occurring in individuals without a family history of the condition. However, arachnoid cysts have been reported in at least three unrelated sets of siblings. In one family, siblings also had microcephaly and intellectual deficit. Arachnoid cysts may be inherited in an autosomal recessive manner in familial cases.[5][6]
Last updated: 7/11/2013

How might arachnoid cysts be treated?

Whether to treat all arachnoid cysts, as well as the method of treatment, has been a subject of controversy in the medical literature. The need for treatment depends mostly upon the location and size of the cyst, as well as whether symptoms are present. Some believe that treatment should be reserved for individuals with symptoms, while others believe that even asymptomatic cysts should be treated to avoid future complications.[4] In the past, doctors have placed shunts in the cyst in order to drain the fluid. However, now that specialized techniques and tools allow for minimally invasive surgery, more doctors are now opting to surgically remove the membranes of the cyst or open the cyst so its fluid can drain into the cerebrospinal fluid and be absorbed.[3][1]
Last updated: 7/11/2013