Tumors of the central nervous system (CNS) constitute a bleak
but vitally important chapter of neurologic medicine. Their importance
derives from their great variety; the numerous neurologic symptoms
caused by their size, location, and invasive qualities; the destruction
and displacement of tissues in which they are situated; the elevation
of intracranial pressure they cause; and, most of all, their lethality.
Slowly, this dismal state of affairs is changing as a result of
advances in anesthesiology, stereotactic and microneurosurgical
techniques, focused radiation therapy and the use of new chemotherapeutic
For clinicians, the following generalizations should be a matter
of general knowledge about brain tumors.
Many tumors, both primary and secondary, occur in
the cranial cavity and spinal canal. Certain ones are much more
frequent than others and are prone to occur in particular age groups.
Secondary metastatic deposits are more common than primary brain
tumors in adults and the opposite is true in children. Furthermore,
certain cancers (breast, lung, melanoma, renal cell cancer) display
a tendency to metastasize to nervous tissue and many others do
not do so.
Some primary intracranial and spinal tumors, such as craniopharyngioma,
meningioma, and schwannoma, have a disposition to grow in particular
parts of the cranial cavity, thereby producing highly characteristic
The presence of diseases such as AIDS, inherited disorders such
as neurofibromatosis, and systemic cancers predisposes to the development
of tumors of the nervous system.
The growth rates and invasiveness of tumors vary; some, like
the glioblastoma, are highly malignant, invasive, and rapidly progressive
and others, like the meningioma, are benign, slowly progressive,
and compressive. These different qualities have substantial clinical
implications, frequently providing the explanation of slowly or
rapidly evolving clinical states and determining a good or poor
Systemic neoplasms, by producing special autoantibodies have
remote effects on the nervous system, quite apart from those caused
by their compressive, infiltrative, or metastatic actions. These remote
effects, referred to as paraneoplasias, often constitute
the initial or only clinical manifestation of the underlying neoplasm.
An excellent general reference on brain tumors is the text edited
by Kaye and Laws.
CNS Tumors and Their Types
Currently, in each year there are an estimated 600,000 deaths
from cancer in the United States. Of these, the number of patients
who died of primary tumors of the brain seems comparatively small (approximately
20,000, half of them malignant gliomas), but in roughly another
130,000 patients the brain is affected at the time of death by metastases.
Thus, in approximately 25 percent of all the patients with cancer,
the brain or its coverings are involved by neoplasm at some time
in the course of the illness. Among causes of death from intracranial
disease in adults, tumor is exceeded in frequency only by stroke,
whereas in children primary brain tumors constitute the most common
solid tumor and represent 22 percent of all childhood neoplasms,
second in frequency ...