Arachnoid
Middle membrane surrounding brain and spinal cord, given its name because of its cobweb-like appearance.

Arachnoid cyst
An arachnoid cyst is a fluid-filled sac found inside the head or spine. The fluid is often cerebrospinal fluid.

Asymptomatic
Without obvious signs or symptoms of disease.

Benign
Something that does not metastasise (spread to another part of body) and treatment or removal is curative.

Brain
Part of the central nervous system (CNS), the brain is the centre of thought and emotion, is involved in the coordination and control of body activities, and interprets information from our senses (sight, hearing, smell, touch, taste).

CNS
Abbreviation for central nervous symptom. Pertains to the brain, cranial nerves and spinal cord. The CNS does not include muscles or peripheral nerves, which are nerves outside of the brain and spinal cord.

Fenestration^*†
An alternative to shunt insertion (see ‘Shunt’) is a surgery called endoscopic fenestration which uses an endoscope (an operative tool with an attached camera) to cut a small hole in the cyst, allowing the fluid to escape into the normal cerebrospinal fluid pathway, relieving intracranial pressure.

Malignant
Something that is likely to metastasise (spread to another part of body).

Meninges
The membranes surrounding the brain and spinal cord: the dura mater (outermost), arachnoid (middle) and the pia mater (innermost).

Neurologist
A physician who diagnoses and treats disorders of the nervous system.

Neurosurgeon
A medically qualified specialist in surgery who has sub-specialised in the surgery of the brain, spinal cord and other nervous tissue. Some neurosurgeons also practise neurology.

Shunt^*†
A shunt is a device implanted within the cyst that drains the fluid away from the cyst and into the ventricles of the brain or into the peritoneum (abdominal space), thus relieving intracranial pressure.

Symptomatic
Indicative of a particular disease or disorder.

Sources

Medline Plus Medical Dictionary
^* Healthline
^† Seattle Children's Hospital in Seattle,Washington (USA).