Case Clinic:
Arachnoid cysts
Munich Re’s medical experts respond to challenging underwriting scenarios
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January 2024
This series presents individual medical cases that feature challenging conditions, uncommon diseases, or an unusual presentation of symptoms. Below, we summarize a case, explain our research and analysis, and suggest an underwriting recommendation. Munich Re’s team of global medical directors routinely conduct rigorous analyses of the latest medical advances so that primary insurers and society alike can benefit from evidence-informed risk assessments. It is our hope that exploring compelling cases will foster a greater understanding of medical research and awareness of new medical innovations and emerging risks while ultimately expanding insurability.
Case: Arachnoid cysts
Munich Re medical's response
What exactly is an “arachnoid cyst”?
- A cyst is a fluid-filled sac that can be located anywhere in the human body. An arachnoid cyst, one of the main types of benign cysts found in the brain, is filled with cerebral spinal fluid and appears within the arachnoid membrane, a thin membrane covering parts of the nervous system in the brain.
How common is this condition, and what are some mortality and morbidity concerns?
Brain cysts are relatively common but sometimes can resemble brain cancer. Often found incidentally, many are asymptomatic. However, they may grow slowly over time, putting pressure on vital brain structures and causing neurological symptoms. Rarely, bleeding may occur.
Only 5% of arachnoid cysts are symptomatic and may include headaches, seizures, hearing loss, dizziness, nausea, and/or vomiting. Typical arachnoid cysts are between 3 and 6 cm in diameter. Most do not grow in size.
The location of arachnoid cysts affects symptoms differently. Suprasellar cysts (generally those located above the pituitary gland) may cause obstruction, leading to hydrocephalus, an abnormal buildup of cerebrospinal fluid.