Understanding Benign and Malignant Brain Tumors

Brain tumors may be primary tumors (derived from cells in the brain) or the result of metastatic seeding from a cancer located elsewhere in the body. The most common cancers that metastasize to the brain are lung and breast.

Brain tumors may be benign or malignant, but in either case will commonly present in one of three ways:

-Symptoms of increased intracranial pressure (chronic morning headaches, vomiting, brain herniation syndromes)

-Seizures

-Focal neurologic deficits (vision changes, paralysis, parasthesias)

Brain cancers may be diagnosed using CT with contrast, MRI (especially for tumors in the posterior fossa or skull base), or with a biopsy of the lesion using computer-guided imaging. Angiography may be used to delineate the blood supply, and may be used to embolize, or close off, the tumor vessels prior to surgery.

Some brain tumors are resectable, meaning they can be surgically removed. Meningiomas, schwannomas and pituitary tumors may be cured by tumor resection. Other types of brain tumors that are in an accessible location may be resected for palliative measures only.

Other treatment options include:

-Radiation therapy- This may be enhanced by brachytherapy, hyperbaric oxygen or gamma knife.

-Cytotoxic chemotherapy.

-Endocrine therapy- The specific medication used is specific for the cell type of the brain tumor. For example, some meningiomas express estrogen receptors so that the breast cancer anti-estrogen drug, Tamoxifen, is therapeutically useful.

-Steroids- These are used to decrease the edema, or swelling, that accompanies brain tumors. Decreasing the brain swelling often provides some symptomatic relief in only 2 to 3 days.

The most common brain cancer in adults is glioblastoma multiforme. This is a grade IV astrocytoma and creates a ring-enhancing lesion on CT. This brain tumor has a poor prognosis and treatment is palliative.

Astrocytomas also develop in children. However, the most common is a pilocytic astrocytoma. This common childhood brain cancer is low grade and has a good prognosis.

Other brain tumors that occur in children include:

-Medullablastomas- Often arising in the cerebellum

-Hemangioblastomas- Associated with Von Hippel Lindau syndrome

-Ependymomas- Often in the 4th ventricle causing hydrocephalus

-Craniopharyngiomas- Derived from Rathke's pouch, calcification is common

Tumors, in addition to glioblastoma multiforme, that occur more commonly in adults include:

-Oligodendrogliomas- Often in the frontal or temporal lobes

-Pituitary adenomas- Prolactin secreting microadenomas are most common. Very large adenomas are usually non-secretory.

-Meningiomas- These occur in the dura mater that surrounds the brain.

-Metastases- Most often occur as multiple lesions at the junction of the gray and white matter.