CD-ROM Today (UK) (Spanish) 15/CDRT.iso/dp/0398/03986.txt

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$Title{Medulloblastoma}
$Subject{Medulloblastoma}
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Copyright (C) 1986, 1987, 1988, 1989 National Organization for Rare
Disorders, Inc.

300:
Medulloblastoma

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.


A Medulloblastoma is a tumor in the cerebellum (a part of the brain),
located in the lower rear portion of the skull (posterior fossa).  About half
of medulloblastomas are confined to the connecting bridge between the two
halves of the cerebellum (vermis), and the other half actually invade the
cerebellum or the brainstem (pons and medulla).

Symptoms

In infants with Medulloblastoma, the first sign of a brain tumor may be
increased head size with no indication of discomfort or other symptoms.  Two
general categories of symptoms can be identified:  those due to increased
pressure inside the skull and those resulting from the tumor's effect on
tissues of the brain.

Increased pressure in the skull may be due to several factors.  Because
the skull is composed of bone and cannot expand to accommodate a growing
mass, the tumor may press on and displace normal brain tissue which is very
easily damaged.  Or the tumor may cause swelling (edema) of the brain or
interfere with spinal fluid excretion which add to the "mass effect".

The most common initial symptom of a Medulloblastoma is vomiting, with or
without nausea, just after waking up in the morning.  This type of vomiting
may be caused by, and an indication of increased intracranial pressure.
However, vomiting can also occur in the absence of pressure due to a
disturbance of the brain itself.  Headache, often severe enough to wake the
child and frequently present in the early morning, is also attributed to
increased intracranial pressure.  After vomiting the child often feels fine
again.  Because this unusual pattern of vomiting is often ignored, confused
with the flu, or attributed to emotions, the tumor often progresses until
other, more specific symptoms occur.

Other symptoms associated with increased intracranial pressure are
irritability, sluggishness or drowsiness (lethargy), personality change and
impaired attention or memory.  The vomiting pattern tends to occur with
increasing frequency as the tumor grows.

The cerebellum coordinates skilled muscle activity such as walking and
speech; signs of cerebellar involvement may be present as the Medulloblastoma
affects normal tissue.  The initial signal of a cerebellar problem is
commonly a change in the way a child walks such as stumbling, or
uncoordinated movements (ataxia or ataxic gait).

Depending on the exact location of the tumor, a variety of additional
symptoms may be present.  Muscle weakness, increased involuntary muscle
contraction (spasticity), change in reflexes such as the knee tap, limp
muscles (hypotonicity), stiff neck often causing a tilt of the head,
imperfect eye coordination such as crossed eyes (strabismus), and rapid
movement of the eyeballs (nystagmus) are frequent signs.  They may also
indicate which brain structures the tumor is affecting.

Neurologists and neurosurgeons are the appropriate medical professionals
to diagnose and treat Medulloblastomas.

Causes

The cause of Medulloblastoma, like most brain tumors, is unknown.

Affected Population

Although Medulloblastomas have been found in newborn babies as well as people
in their 70's, this tumor is most commonly found in children between 4 and 8
years of age, with a peak incidence at 5 1/2 years.

Boys of this age are twice as likely to have this type of tumor as girls,
but the sexual predisposition tends to lessen with increasing age.  Two other
peaks of occurrence have been reported during childhood; one at 3 years and
one at 7-9 years.  A smaller peak exists between 20 and 24 years of age.
Eighty percent of all Medulloblastomas occur in children 15 years or younger.

Therapies:  Standard

It is common for Medulloblastoma to block the normal flow of spinal fluid,
causing it to accumulate in the brain.  Shunting may be necessary to remove
the excess fluid and decrease intracranial pressure prior to removal of the
tumor.  The use of this procedure is controversial, due to the risk of
spreading the tumor (metastasis) via the shunt to other parts of the body.

SURGERY--Surgical removal of the tumor (posterior fossa craniectomy) is
the treatment of choice.  This surgery is necessary to remove the bulk of the
tumor and to allow other treatment methods, such as chemotherapy or
radiation, to be more effective.

RADIATION--This tumor tends to be easily destroyed by radiation.
Radiation therapy usually begins about a week after surgery and should
include irradiation of the entire brain and spine, with a booster dose to the
posterior fossa.  The Medulloblastoma may spread throughout the brain and
spinal cord (neuroaxis), hence the entire central nervous system must be
irradiated.  Some hospitals report a 60%-70% 5 year survival rate in
Medulloblastoma patients when the tumor has been apparently totally removed,
followed by radiation treatment.

CHEMOTHERAPY--High risk patients with Medulloblastoma are those who are
less than 3 years old, having extensive tumor before surgery, marked residual
tumor after surgery, or those whose tumor has spread beyond the cerebellum.
They may benefit from chemotherapy such as Vincristine or CCNU.  This
additional drug treatment is prescribed in the hope that it will delay or
prevent recurrence of the tumor.

Therapies:  Investigational

Ongoing research into new treatments for Medulloblastoma is conducted at the
National Cancer Institute (see "Resources" section of this entry).

This disease entry is based upon medical information available through
June 1988.  Since NORD's resources are limited, it is not possible to keep
every entry in the Rare Disease Database completely current and accurate.
Please check with the agencies listed in the Resources section for the most
current information about this disorder.

Resources

For more information on Medulloblastoma, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     Association for Brain Tumor Research
     2910 West Montrose Ave.
     Chicago, IL 60618
     [phone]

     American Cancer Society
     1599 Clifton Rd., NE
     Atlanta, GA  30329
     [phone]

     NIH/National Cancer Institute
     9000 Rockville Pike, Bldg. 31, Rm. 1A2A
     Bethesda, MD 20892
     1-800-4-CANCER

The National Cancer Institute has developed PDQ (Physician Data Query), a
computerized database designed to give doctors quick and easy access to many
types of information vital to treating patients with this and many other
types of cancer.  To gain access to this service, a doctor can contact the
Cancer Information Service offices at 1-800-4-CANCER.  Information
specialists at this toll-free number can answer questions about cancer
prevention, diagnosis, and treatment.

References

ABOUT MEDULLOBLASTOMA; W. Kretzmer et al.:  Association for Brain Tumor
Research, 1985.