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Brain Tumors 

More than 18,000 new cases of primary brain tumors are treated each year in the United States. Metastases are even more frequent and contribute considerably to suffering and death from brain tumor or brain cancer. The diversity of brain tumors makes it important.

About a third of primary brain tumors can be called benign. Meningiomas and acoustic neuromas are good examples. They grow slowly, often can be removed completely, and rarely recur. The concept of malignancy in the central nervous system (CNS) has a different meaning from that which applies to systemic cancers. The term "malignant" has nothing to do with metastasis out of the CNS, which is extraordinarily rare. It has everything to do with anatomic location and the possibility of complete surgical removal. Unless a tumor can be completely excised to the last cell, all intracranial neoplasms are potentially malignant.

Lung (37) Meningioma (80) Glioblastoma (47)
Breast (19) Acoustic neuroma (10) Anaplastic astrocytoma (24)
Melanoma (16) Pituitary adenoma (7) Astrocytoma (15)
Colorectum (9) Other (3) Oligodendroglioma (5)
Kidney (8)
Lymphoma (2)
Other (11)
Other (7)
*These figures, given in parentheses, can be extremely variable from one center to another, depending on referral pattern. They are given here as general estimates based upon many published series.

A. Astrocytic tumors
  1. Astrocytoma
    a. Fibrillary
    b. Protoplasmic
    c. Gemistocytic
  2. Pilocytic astrocytoma
  3. Subependymal giant cell astrocytoma (ventricular tumor or tuberous sclerosis)
  4. Astroblastoma
  5. Anaplastic (malignant) astrocytoma
B. Oligodendroglial tumors
  1. Oligodendroglioma
  2. Mixed oligoastrocytoma
  3. Anaplastic (malignant) oligodendroglioma
C. Ependymal and choroid plexus tumors
    a. Myxopapillary ependymoma
    b. Papillary ependymoma
    c. Subependymoma
  2. Anaplastic (malignant) ependymoma
  3. Choroid plexus papilloma
  4. Anaplastic (malignant) choroid plexus papilloma
D. Pineal cell tumor
  1. Pineocytoma (pinealcytoma)
  2. Pineoblastoma (pinealoblastoma)
E. Neuronal tumors
  1. Gangliocytoma
  2. Ganglioglioma
  3. Ganglioneuroblastoma
  4. Anaplastic (malignant) gangliocytoma and ganglioglioma
  5. Neuroblastoma
F. Poorly differentiated and embryonal tumors
  1. Glioblastoma
    a. Glioblastoma with sarcomatous component (mixed glioblastoma and sarcoma)
    b. Giant cell glioblastoma
  2. Medulloblastoma
    a. Desmoplastic medulloblastoma
    b. Medullomyoblastoma
  3. Medulloepithelioma
  4. Primitive polar spongioblastoma
  5. Gliomatosis cerebri

Brain tumors present in two patterns, not necessarily mutually exclusive. One consists of nonfocal symptoms of increased intracranial pressure, such as headaches, nausea, vomiting, confusion, and lethargy. The other consists of symptoms or signs of focal brain dysfunction, such as hemianopia, hemiparesis, cranial nerve palsies, or focal seizures. Such signs of focal brain dysfunction may have convincing localizing value even before an image of the brain is made by computed tomography (CT) or



In almost every instance in which a brain tumor is suspected on the basis of the combined results of history, physical findings, and imaging studies, the first consideration is its surgical resectability. Exceptions exist, such as in a case of multiple brain metastases in a patient with known systemic cancer. Patients with single brain metastases, defined by MRI, may be candidates for surgical resection of the metastasis, depending on the systemic medical status. It is unproductive to embark on an 

Although small meningiomas or acoustic neuromas usually do not require treatment to reduce intracranial pressure, in the majority of brain tumor patients it is appropriate to start administration of dexamethasone promptly. The purpose is to reduce intracranial pressure, which accompanies the majority of brain tumors, and to relieve neurologic symptoms caused by peritumoral brain edema. The long biologic half-life of dexamethasone and steady action on the brain have made it the steroid of choice for treating patients with brain tumors. It should be started with an oral dose of 24 mg, followed with 8 mg twice daily. It is well absorbed by

About 20% of brain tumor patients develop seizures at some time, even if they do not have seizures at the time of diagnosis. It is conventional but not clearly effective to treat all patients with supratentorial tumors with anticonvulsants before surgery. Most patients with acoustic neuromas or other posterior fossa tumors have a low probability of convulsive seizures and do not need such drugs. Phenytoin is the best initial drug because it can be administered either intravenously or orally, unlike either carbamazepine or valproic acid, which can only be used orally. An intravenous drug is especially useful for continuation during the perioperative period. If required, patients may be switched easily to alternative oral drugs later. Phenytoin should be started


Although complete excision of a brain tumor is the ultimate goal in every case, this is not always possible. Even potentially curable tumors, such as meningiomas or acoustic neuromas, may reside in positions that make complete resection technically impossible. Malignant gliomas lack microscopic boundaries, even though they may appear by imaging studies to have well-defined limits. How much surgical success can be achieved with these tumors depends on several factors, including the tumor's proximity to indispensable areas, the skill and experience of the neurosurgeon and the preoperative level of neurologic function.