Neuroscience Clerkship

 

 

COMMON BRAIN TUMORS IN CHILDREN


Tumor Location by Age

Age  Supratentorial Infratentorial
< 2 yrs 75% 25%
2-10 yrs 40% 60%
10-20 60% 40%
Adult 75% 25%


Pediatric CNS Tumor Histology

Supratentorial gliomas 30% - 35%

Primitive neuroectodermal tumor 20 -25%

Cerebellar juvenile pilocytic astrocytoma 15%

Brainstem gliomas 15%

Ependymoma 15% 5%

Choroid plexus papilloma 10%

Craniopharyngiomas 5%

Pineal region tumors 5%

Spinal canal 5%

Rhabdoid tumors 5%


 

 

 

Supratentorial Glioma


Two-thirds of tumors are low-grade

Half of the low-grade tumors are astrocytomas; half have more exotic pathology.

If the tumors are resectable some can be cured

Prognosis depends upon tumor histology, tumor location, and extent of resection

Children with malignant tumors and maximal therapy survive 1-3 years.


 

 

 

Primitive Neuroectodermal Tumors


Malignant tumors that occur throughout the CNS with similar histology and prognosis, but that were given different names in the past depending on location

Medulloblastomas arise in the fourth ventricle, and comprise 30% of posterior fossa tumors of childhood

Medulloblastoma is the most common malignant brain tumor of childhood

Medulloblastomas occur in adults infrequently

The 5 year survival of pediatric medulloblastoma has improved to about 70%, on the basis of complete surgical resection and adjuvant therapy which usually includes craniospinal radiation (because of the strong tendency of medulloblastoma to seed the subarachnoid space) and often chemotherapy.


 

 

 

Juvenile Pilocytic Astrocytoma


Tumors occur in the cerebellar hemispheres, frequently with cysts

Gross total resection can cure >95% in the posterior fossa

Pathology is WHO grade I, the same pathology as optic and hypothalamic astrocytomas

In contrast to cerebellar astrocytomas, astrocytomas of the optic apparatus and hypothalamus are generally not amenable to gross total resection.


 

 

 

Brainstem Glioma


Diffusely infiltrative unresectable tumors that show a poor response to radiation and chemotherapy

Some midbrain tectal gliomas remain dormant but may cause obstructive hydrocephalus

Pontine tumors usually present with long tract symptoms and signs and cranial palsies, but not hydrocephalus

Pathology can vary from WHO I to IV, but the prognosis is typically dismal (almost all die by 18 months after diagnosis).


 

 

 

Ependymoma


Malignant tumor that often arises in the posterior fossa, but is found throughout the CNS

Tumor tends to extrude through the outlets of the fourth ventricle and encase cranial nerves and vessels

Typically present with symptoms of obstructive hydrocephalus, but frequently have lower cranial nerve palsies after resection

The prognosis is generally significantly worse than that for medulloblastoma. With complete resection and radiation, survival may reach 40% at 5 years. Chemotherapy is not effective. Late recurrences occur.