Choroid Plexus Tumors

views updated

Choroid plexus tumors

Definition

Choroid plexus tumors (CPTs) are rare abnormal growths on a part of the brain called the choroid plexus. The choroid plexus is the structure in the brain that produces the cerebrospinal fluid that coats the brain and spinal cord.

Description

There are two types of CPT: choroid plexus papilloma (CPP) and choroid plexus carcinoma (CPC). CPPs account for the majority of all CPTs.

A CPP is a benign, slow-growing, wart-like tumor that tends to grow on the surface of the choroid plexus. CPPs can spread by growing and by multiplying, just like warts, but they do not spread (metastasize) to organs that are not directly attached to the brain. A CPC is a malignant slow-growing tumor that tends to invade healthy brain tissue. CPCs can metastasize to distant parts of the body.

A primary brain tumor is a tumor that begins in the brain, as opposed to a secondary (or metastatic) brain tumor, which begins in another organ and metastasized to the brain. CPPs make up approximately 1% of primary brain tumors in adults and 3% of primary brain tumors in children.

Demographics

CPTs occur in approximately two of every one million people. CPTs can occur in people of any age, but greater than 70% of all CPTs occur in children younger than two years of age. When CPPs occur in children, they tend to be located in the uppermost portion of the spinal fluid pathway (the lateral ventricles). When they occur in adults, they tend to be located in the lower portion of the spinal fluid pathway in the brain (the fourth ventricle). CPCs occur almost exclusively in children, most under the age of two years, and are almost always located in the lateral ventricles.

CPTs occur with equal frequency in members of all races and ethnic groups. There does not appear to be any relationship of CPTs to any geographic region. Males and females are affected in equal numbers by CPTs.

Causes and symptoms

The cause, or causes, of CPTs are not known. In early 2001, ongoing investigations attempted to determine if environmental factors, genetic factors, viruses, or other factors caused primary brain tumors. Primary brain tumors are not contagious.

The symptoms of CPTs are the result of increased pressure in the fluid within the skull (intracranial hyper-tension). These symptoms include:

nausea
vomiting
irritability
headache
vision disturbances
enlargement of the head
seizures

CPCs may also be accompanied by:

bleeding (hemorrhage) at the site of the tumor
weakness or paralysis on the side of the body opposite to the side of the brain where the tumor is located.

Diagnosis

The diagnosis of CPTs begins in the doctor's office. After taking a complete medical history, the doctor will perform a basic neurological examination. This examination involves:

testing eye reflexes, eye movement, and pupil reactions
testing hearing with a tuning fork or ticking watch
reflex tests with a rubber hammer
balance and coordination tests
pin-prick and cotton ball tests for sense of touch
sense of smell tests with various odors
facial muscle tests: smiling, frowning, etc.
tongue movement and gag reflex tests
head movement tests
mental status tests: asking what year it is, who the president is, etc.
abstract thinking tests: asking for the meaning of a common saying, such as "every cloud has a silver lining."
memory tests: asking to have a list of objects repeated, asking for details of what a patient ate for dinner last night, etc.

If the doctor suspects a brain tumor may be present, further diagnostic tests will be ordered. These tests are performed by a neurological specialist. Imaging tests that may be ordered include:

computed tomography (CT scan)
magnetic resonance imaging (MRI)

Other tests may include:

a lumbar puncture , or spinal tap, to examine the cerebrospinal fluid
an electroencephalogram (EEG), which measures the electrical activity of the brain

Treatment team

Treatment of any primary brain tumor, including the CPTs, is different from treating tumors in other parts of the body. Brain surgery requires much more precision than most other surgeries. Also, many medicinal drugs cannot cross the blood-brain barrier. Therefore, the therapies that are used to treat CPTs, and the side effects of these therapies, are quite complex.

The most up-to-date treatment opportunities are available from experienced, multidisciplinary medical professional teams made up of doctors, nurses, and technologists who specialize in cancer (oncology), neurology, medical imaging, drug or radiation therapy , and anesthesiology.

Clinical staging, treatments, and prognosis

CPTs and other primary brain tumors are diagnosed, or staged, in grades of severity from I to IV. Grade I tumors have cells that are not malignant and are nearly normal in appearance. Grade II tumors have cells that appear to be slightly abnormal. Grade III tumors have cells that are malignant and clearly abnormal. Grade IV, the most severe type of brain tumor, contains fast-spreading and abnormal cells. The standard treatment for all grades of CPTs is surgery to completely remove the tumor or tumors. This surgery is generally aided by an image guidance system that allows the surgeon to determine the most efficient route to take to the location of the tumor.

Approximately one-half of CPT patients gain relief of the increased intracranial pressure after complete removal of their tumors. The other half require a spinal fluid shunt to allow drainage of the excess fluid.

In some instances of CPC, the tumor is inoperable. Patients with inoperable CPCs are generally treated with radiation therapies. CPPs are highly resistant to radiation treatment, so these therapies are not used for CPPs.

As of 1999, 8.6% of patients who had surgery to remove CPTs died within five years of the surgery. One-half of these patients (4.3%) died during the surgery itself.

Alternative and complementary therapies

There are no effective alternative treatments for CPTs other than surgery and radiation therapies in the case of inoperable CPCs.

Coping with cancer treatment

Most patients who undergo brain surgery to remove their tumors can resume their normal activities within a few days of the operation.

Clinical trials

There were 19 clinical trials underway in early 2001 aimed at the treatment of CPTs. More information on these trials, including contact information, may be found by conducting a clinical trial search at the Web site of the National Cancer Institute, CancerNet (http://cancernet.nci.nih.gov/trialsrch.shtml).

Prevention

Because the causes of CPTs are not known, there are no known preventions.

Special concerns

Repeat surgery may be necessary for CPTs because these tumors sometimes redevelop. Careful monitoring by the medical team will be required.

Resources

BOOKS

Scott, R. Michael, and John Knighty. "Choroid Plexus Papilloma." In Brain Tumors: An Encyclopedic Approach, edited by Andreeo H. Kaye. New York: Churchill Livingstone, 1995, pp. 505-524.