Choroid Plexus Definition
The choroid plexus, a highly vascularized portion of the pia mater, forms finger-like projections that intricately weave into the ventricles of the brain.
These projections are responsible for the secretion of cerebrospinal fluid and represent a crucial component of the blood-brain barrier that ensures the safety of the central nervous system from hazardous substances. In essence, the choroid plexus serves as the chief fountainhead of various constituents of the cerebrospinal fluid.
A confluence of capillaries and specialized ependymal cells form the intricate network that constitutes the choroid plexus. Despite its immense importance, the choroid plexus is susceptible to the onset of a rare but benign tumor called choroid plexus papilloma that can develop in the epithelium of the choroid plexus.
Choroid Plexus Location
The choroid plexus resides in the innermost layer of the meninges (pia mater) which is in close contact with the cerebral cortex and spinal cord. It is a highly organized tissue that lines all the ventricles of the brain except the frontal/occipital horn of the lateral ventricles and the cerebral aqueduct.
The structure known as the choroid plexus, which is located in the cerebral ventricles of the brain, is composed of choroidal epithelial cells, permeable capillaries, and loose connective tissue. Its primary function is to generate cerebrospinal fluid (CSF) while forming the blood-CSF barrier, in conjunction with arachnoid and arachnoid villi.
The ventricles of the brain, which are fluid-filled cavities situated deep in the cerebral cortex, are lined by the choroid plexus, with the exception of the frontal/occipital horn of the lateral ventricles and the cerebral aqueduct. The choroid plexus is present in the left and right lateral ventricles, as well as the third and fourth ventricles.
Branches of the posterior inferior cerebellar arteries supply the choroid plexus, which is found in the posterior medullary velum that partially creates the roof of the fourth ventricle. The choroid plexus within the lateral ventricles is situated in the superomedial part of the inferior horn and the anteromedial region of the body.
Meanwhile, the choroid plexus in the third and fourth ventricles can be located along the roof of the third ventricle and the medullary portion of the fourth ventricle, respectively.
Choroid plexus cysts are generally benign cysts that form as a result of the folding of the neuroepithelium during fetal development. The lateral ventricles are the most common location for these cysts, which can be detected prenatally through the use of a fetal ultrasound.
Conversely, choroid plexus tumors can develop from the choroid plexus and potentially grow, spread to other areas of the central nervous system, and/or obstruct the ventricular flow of CSF, leading to an accumulation of fluid.
Choroid Plexus Function
The choroid plexus (ChP) is a secretory tissue found in each of the brain ventricles, the main function of which is to produce cerebrospinal fluid (CSF).
The choroid plexus is a structure located within the cerebral ventricles of the brain. It is composed of choroidal epithelial cells, loose connective tissue, and permeable capillaries. The choroid plexus produces cerebrospinal fluid (CSF) and regulates its composition.
CSF provides protective buoyancy for the brain and acts as a medium for the glymphatic filtration system that facilitates the removal of metabolic waste from the brain and the exchange of biomolecules and xenobiotics into and out of the brain.
The choroid plexus is present in each of the four ventricles of the brain. In the lateral ventricles, it is found in the body and continued in an enlarged amount in the atrium. There is no choroid plexus in the anterior horn.
In the third ventricle, there is a small amount in the roof that is continuous with that in the body, via the interventricular foramina, the channels that connect the lateral ventricles with the third ventricle. A choroid plexus is in part of the roof of the fourth ventricle.
Several structural issues can arise from the choroid plexus, and a number of neurological conditions affect and are impacted by the choroid plexus and/or CSF flow. Cysts of the choroid plexus are small growths, and they are usually benign. Choroid plexus papillomas are rare tumors that arise from the choroid plexus.
Cerebrospinal Fluid
Cerebrospinal fluid (CSF) is a clear, colorless plasma-like fluid that surrounds and bathes the central nervous system (CNS). It circulates through a system of cavities found within the brain and spinal cord, including the ventricles, subarachnoid space of the brain and spinal cord, and the central canal of the spinal cord.
The CSF is produced by a specialized tissue called the choroid plexus, which is located in the walls of the lateral ventricles and in the roofs of the third and fourth ventricles. The choroid plexus secretes the CSF through numerous villi.
The CSF performs vital functions, including providing nourishment, waste removal, and protection to the brain. It supports the brain and provides lubrication between surrounding bones and the brain and spinal cord.
When an individual suffers a head injury, the fluid acts as a cushion, dulling the force by distributing its impact. The fluid helps to maintain pressure within the cranium at a constant level. An increase in the volume of blood or brain tissue results in a corresponding increase in the volume of CSF.
The exact method of the formation of the CSF is uncertain. After originating in the ventricles of the brain, it is probably filtered through the nervous-system membranes (ependyma). The CSF is continually produced, and all of it is replaced every six to eight hours.
The fluid is eventually absorbed through respiration, pressure from the veins, and head and body movements. The choroid plexus also regulates the production and composition of the CSF, which provides the protective buoyancy for the brain.
Choroid Cyst
Choroid cysts are fluid-filled sacs that form in the choroid plexus, which is the part of the brain that produces cerebrospinal fluid (CSF). Choroid plexus cysts are relatively common in normal fetuses, occurring in about 1 to 2 percent of normal babies.
Most fetuses with a choroid plexus cyst are normal, and the cysts are not usually dangerous. However, in a very small percentage of fetuses with choroid plexus cysts, there is an associated chromosome disorder called trisomy 18.
Fetuses with trisomy 18 have an extra copy of chromosome 18 and frequently have other abnormalities. Therefore, when choroid plexus cysts are detected, doctors are concerned that the fetus may have trisomy 18.
Choroidal fissure cysts, also known as choroid fissure cysts, are a different type of cyst that occur within the choroidal fissure, which is a groove in the brain that separates the cerebral hemisphere from the cerebellum. Choroidal fissure cysts are usually asymptomatic and discovered incidentally.
They are usually small, ranging around 1-2 cm in diameter, and are round on axial and coronal images, with a characteristic spindle or ovoid shape paralleling the long axis of the temporal lobe and choroid fissure on sagittal images.
Choroidal fissure cysts may represent either neuroepithelial cysts or arachnoid cysts. They are usually benign and do not require treatment unless they cause seizures due to mass effect on the temporal lobe.
The choroid plexus is a protective barrier that lines the inner surface of the ventricles of the brain and produces cerebrospinal fluid (CSF). Cysts or tumors can form in the choroid plexus, and the cysts are not usually as dangerous as the tumors.
Choroid plexus tumors can develop from the choroid plexus, potentially growing, spreading to other areas of the central nervous system, and obstructing the ventricular flow of CSF, causing fluid accumulation. Choroid plexus tumors include papilloma and carcinoma.
Choroid Cancer
The choroid plexus is a part of the brain that produces cerebrospinal fluid (CSF), which provides nourishment and cushioning for the brain and spinal cord. The choroid plexus is located within the cerebral ventricles and lines the inner surface of the ventricles of the brain.
It is made of choroidal epithelial cells, loose connective tissue, and permeable capillaries. The choroid plexus lines the left and right lateral ventricles and the third and fourth ventricles.
Cysts or tumors can form in the choroid plexus, and the cysts are not usually as dangerous as the tumors. Choroid plexus cysts are present in about 1 to 2 percent of normal fetuses and are relatively common in normal fetuses.
However, in a very small percentage of fetuses with choroid plexus cysts, there is an associated chromosome disorder called trisomy 18. Fetuses with trisomy 18 have an extra copy of chromosome 18, and when choroid plexus cysts are detected, there is a concern that the fetus may have trisomy 18. Trisomy 18 is rare, present in less than 1 in 3,000 newborns.
Choroid plexus tumors can develop from the choroid plexus, potentially growing, spreading to other areas of the central nervous system, and/or obstructing the ventricular flow of CSF, causing fluid accumulation.
Choroid plexus tumors include papilloma. Treatment for choroid plexus tumors may include surgery, radiation therapy, and chemotherapy.
Choroid Plexus Fissure
The choroid plexus fissure is a cleft of the medial surface of the cerebral hemisphere that runs immediately above the hippocampus and forms the medial wall of the lateral ventricle and attachment site for the choroid plexus.
The choroid plexus is the part of the brain that makes cerebrospinal fluid, which normally bathes and protects the brain and spinal column. The choroid plexus is located within the cerebral ventricles and is made of choroidal epithelial cells, loose connective tissue, and permeable capillaries.
The choroid plexus originates at the inferior choroidal point of the choroidal fissure, which is located just posterior to the hippocampal head.
The choroid plexus also forms the blood-CSF barrier alongside arachnoid and arachnoid villi. The blood-CSF barrier is a selective barrier that regulates the exchange of substances between the blood and cerebrospinal fluid.
The choroid plexus is responsible for producing cerebrospinal fluid, which performs vital functions, including providing nourishment, waste removal, and protection to the brain.
Choroid plexus cysts are present in 1 to 2 percent of normal fetuses. However, in a very small percentage of fetuses with choroid plexus cysts, there is an associated chromosome disorder called trisomy 18.
Fetuses with trisomy 18 have an extra copy of chromosome 18. Therefore, when choroid plexus cysts are present, there is a concern that the fetus may have trisomy 18.
Hydrocephalus
Hydrocephalus is a neurological disorder that occurs when there is an abnormal buildup of cerebrospinal fluid (CSF) in the ventricles deep within the brain. This excess fluid causes the ventricles to widen, putting harmful pressure on the brain’s tissues.
Hydrocephalus may be present at or shortly after birth, or may result over time from damage or injury. There are different types of hydrocephalus, including communicating hydrocephalus, non-communicating hydrocephalus, normal pressure hydrocephalus, and hydrocephalus ex-vacuo.
Communicating hydrocephalus occurs when the flow of CSF is blocked after it exits the ventricles. This form is called communicating because the CSF can still flow between the ventricles and the passages between them remain open.
Non-communicating hydrocephalus, also called obstructive hydrocephalus, occurs when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles. Normal pressure hydrocephalus (NPH) is a form of communicating hydrocephalus that can strike people at any age, but it is most common among the elderly. Hydrocephalus ex-vacuo results from brain damage caused by stroke or injury.
The treatment for hydrocephalus depends on the underlying cause and severity of the condition. In some cases, surgery may be necessary to remove the blockage or to implant a shunt to drain the excess fluid.
Choroid plexus cauterization is another surgical procedure that uses electric current to burn the CSF-producing tissue in the choroid plexus. In some cases, medication may be used to reduce the production of CSF. Early diagnosis and treatment are important to prevent complications and improve outcomes for people with hydrocephalus.
