Some of the most common categories of pediatric brain tumors are listed here and will provide you with an introduction into these types of pediatric brain tumors.

While Kyla Miller Foundation wishes to provide comprehensive information for our audience, we realize that other foundations and research institutions have already published the information you seek.  The information listed here has been gathered from comprehensive documentation published by the American Brain Tumor Association and St. Jude Children's Research Hospital.  KMF will provide summary information to get you started and drop-off points for published information under the Resources section of our website.  KMF is in no way affiliated with American Brain Tumor Association or St. Jude Children's Research Hospital.
 

Medulloblastoma is a rapidly growing tumor of the cerebellum - the area of the brain that controls balance, posture and speech.  In children, medulloblastoma typically occurs in the connective tissue between the cerebellum and two hemispheres of the brain.  It is the most common type of brain tumor arising from immature cells, afflicting about 20% of children diagnosed with brain tumors.

There are seven different classifications of medulloblastoma:

• classic medulloblastoma
• desmoplastic nodular medulloblastoma
• large-cell or anaplastic medulloblastoma
• medulloblastoma with neuroblastic or neuronal differentiation
• medulloblastoma with glial differentiation
• medullomyoblastoma
• melanotic medulloblastoma

Although the cause of medulloblastoma is unknown, significant strides are being made in understanding its biology.  For example, changes in chromosomes 17, 1, 7, 8, 9, 10q, 11 and 16 may play a part.  

Symptoms of medulloblastoma include flu-like symptoms - irritability, loss of appetite, lethargy.  "Morning sickness" may be another symptom - headache, nausea, vomiting - upon waking up in the morning.  Dizziness, clumsiness and staggered walking are also symptoms since the area of concern control motor coordination.

With today's treatment options, 70% - 80% of children diagnosed with average-risk medulloblastoma survive free of disease five years from diagnosis.  Children with high-risk medulloblastoma have a 60% - 65% chance of living disease-free for five years.

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Primitive Neuroectodermal Tumor (PNET)

PNET tumors appear identical to medulloblastoma under the microscope; however, this tumor occurs in the cerebrum versus the cerebellum.  The cerebrum control thought, movement and sensation.  PNET tumors are highly malignant and tend to spread throughout the central nervous system as tumor cells travel through the cerebrospinal fluid to the spine.

Symptoms of PNET tumors include "morning sickness", headache, nausea, vomiting, fatigue, lethargy, double-vision, disturbances in ocular movement, back and/or leg pain, slow developing weakness of the lower extremities and incontinence.

The five-year survival rate for children diagnosed with PNET tumors is 50% - 60%; however, relapse cases are almost always fatal.

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Ependymoma is a type of tumor arising from ependymal cells that line the ventricles of the brain and the center of the spinal cord that produce and store cerebrospinal fluid.  About 6% of pediatric brain tumors are ependymomas.

Types of ependymomas include:

• myxopapillary ependymoma - occurs in the lower part of the spinal column
• subependymoma - occurs near a ventricle
• ependymoma - occurs along the ventricle system and through the spinal cord
• anaplastic ependymoma - occurs below the ventricle and is more aggressive

Symptoms of ependymoma include nausea, vomiting and headaches as pressure increases due to the tumors blocking cerebrospinal fluid from draining properly.  Ependymomas occurring near the brain stem may cause the eyes to cross, balance issues and trouble walking.  Seizures are also common with severe ependymomas.  Ependymomas occurring in the spinal column will cause tingling sensations, numbness and weakness as well as incontinence.

Survival rates for children with ependymoma vary with the highest rate occurring when surgical removal is successful.

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Astrocytoma tumors come in a variety of forms, and they are named after their star-shaped cells called astrocytes.  They are the most common type of primary brain tumor.  Astrocytomas are known by many different names, depending on their characteristics.  The terms "astrocytoma" and "glioma" are used interchangeably.

Astrocytomas are categorized as either low-grade or high-grade.  While low-grade astrocytomas account for the majority of astrocytomas in children, high-grade astrocytomas account for the majority of astrocytomas in adults.  About 80% of diagnosed astrocytomas in children are low-grade.

There are several different types of low-grade astroctyomas:

• juvenile pilocytic astrocytoma (JPA)
• fibrillary (diffuse) astrocytoma
• pleomorphic xanthoastrocytoma (PXA)
• diffuse astrocytoma
• desembryoplastic neuroepithelial tumor (DNET)

JPA's typically grow in the cerebellum (the part of the brain that controls balance) and are more common in children than adults.  Their boundaries are sharply defined and so surgery is most often the "cure" for this type of tumor.  JPA's are Grade I tumors.

Fibrillary (or diffuse) astrocytomas must be distinguished between JPA's and are found in the brain stem.  Fibrillary astrocytomas are the most common form of low-grade astrocytoma.  They are slow growing but have tentacles that spread into normal brain tissue.  Therefore total surgical removal is uncommon.  This type of tumor typically grows in the cerebral hemispheres where thought process is controlled.  Fibrillary astrocytomas are Grade II tumors.

PXA's tend to grow superficially in the brain, and so like pilocytic astroctyomas they are generally "cured" with surgery.  PXA tumors are Grade I tumors.

DNET tumors tend to grow in the temporal regions of the brain.  DNET tumors are Grade xx tumors.

The most common types of high-grade astrocytoma are:

• anaplastic astrocytoma (AA)
• glioblastoma multiforme (GBM)

Anaplastic means malignant.  AA and GBM tumors account for about 10% of all pediatric brain and spinal cord tumors.  AA tumors occur sporadically without identifiable cause.  This is a Grade III tumor and has an increased number of cells, abnormal cells and nuclei, increased proliferation of cells and increased growth of blood vessels.  AA tumors have a tendency to infiltrate adjacent brain tissue and spread outside the central nervous system.

GBM tumors are Grade IV astrocytomas and are fatal.  There are very rare cases documented where children with GBM survive beyond five years.  Most children with GBM die within 18 months of diagnosis.  Those that can make it beyond 18 months generally succumb around 3 years after diagnosis.

Symptoms for astrocytomas generally include headaches, nausea and vomiting, as well as other symptoms depending which part of the brain the tumor is growing.  Like all brain tumors, symptoms will begin gradually and intensify as the tumor grows.

Survival rates for children with low-grade astrocytomas are as high as 90% five years after diagnosis.  Prognosis for children with high-grade astrocytomas is dismal, and in the rare instances where the child does survive they tend to have severely impacted quality of life issues.

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The brain stem is the central hub of the brain and central nervous system connecting the brain and the spinal cord.  It includes the midbrain, pons and medulla.  Brain stem gliomas account for approximately 10% of pediatric brain tumors.

Bran stem gliomas that arise from the midbrain have a much better prognosis than other brain stem gliomas.  Tumors in this region often affect the nerves that control eye muscles.  If midbrain gliomas block the flow of cerebrospinal fluid, the patient may suffer from increased pressure with headaches and vomiting.

Brain stem gliomas affecting the medulla will cause problems with swallowing as well as weakness in the arms and legs.

Pontine gliomas - brain stem gliomas in the pons - affect cranial nerves, and patients will have trouble with the eye and face muscles as well as problems swallowing.  Other areas affected by pontine gliomas include:

• double vision
• inability to close the eyelids completely
• one side of the face droops
• difficulty chewing and swallowing
• weakness in arms and legs
• difficulty with speech
• difficulty walking

While brain stem gliomas of the midbrain and medulla have a 65% - 90% outcome, it is uncommon for patients with pontine gliomas to survive beyond 12 to 14 months.

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Germ cell tumors in the brain are rare and account for about 4% of brain tumors diagnosed in children.  They are commonly diagnosed during adolescence and affect boys more than girls.  Germ cell tumors can spread to other parts of the brain and spinal cord but originate in the center of the brain around the suprasellar and pineal regions.

Symptoms of suprasellar tumors present themselves with hormonal problems, while pineal region germ cell tumors cause increased pressure with headaches and vomiting.

Prognosis for a type of germ cell tumor called germinoma is extremely high, with about 85% of patients being cured through radiation therapy alone.

Other types of germ cell tumors are less sensitive to radiation where cure rates are only about 20%.

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