Figure 3: MRI of three metastatic brain tumors

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Figure 1: MRI of the brain that demonstrates a large right frontal meningioma.  Note how the tumor exhibits a homogenous enhancement pattern (ie the mass has the same intensity throughout)

Brain

Brain Tumors


There are many different types of brain tumors.  These can generally be divided into three categories in the adult population: 
Meningiomas, Primary brain tumors (Astrocytomas), and Metastatic tumors.  Meningiomas are generally benign, slow-growing tumors that originate from the arachnoid, which is a thin covering layer surrounding the brain (and is part of the "meninges").  Meningiomas account for approximately 15-20% of all brain tumors.  Since the vast majority of meningiomas are benign and slow-growing, many of them do not require treatment at all and can be observed with serial MRI scans at periodic intervals.  Large meningiomas can result in significant neurologic deficits from mass effect on the surrounding brain, however.  Therefore, indications for treatment typically involve progressive growth over time demonstrated on serial MRIs or neurologic deficits attributable to mass effect from the tumor.  Complete surgical resection is often curative with meningiomas, and this renders surgery the treatment modality of choice for most tumors.  Other forms of treatment typically involve radiation, and this is usually reserved for meningiomas in difficult-to-access regions of the brain. Meningiomas typically have a characteristic enhancement pattern on MRI scans (Figure 1).

Primary brain tumors in most adults actually arise from the support cells within the brain (called astrocytes), and not the neurons themselves.  These tumors are called astrocytomas, and their biological behavior can vary tremendously.  Astrocytomas are typically given a "Grade" based on how many aggressive characteristics are present within the tumor when examined under a microscope by a Pathologist.  Astrocytomas are graded from I to IV, with grade I tumors being the least aggressive and grade IV tumors being the most aggressive.  Unfortunately Grade IV tumors are most commonly encountered in the adult population.  Grade IV astrocytomas are also referred to as "Glioblastoma multiforme", and it is associated with a median survival of approximately one year.  Glioblastomas often exhibit prominent enhancement patterns on MRI with severe mass effect upon the surrounding brain (Figure 2).

Metastatic brain tumors are a result of cancer that arises elsewhere in the body and then spreads (or "metastasizes") to the brain.  Metastatic brain tumors most commonly result from lung cancer, breast cancer, kidney (renal cell) cancer, gastrointestinal cancers, and melanoma (Figure 3).  The treatment of metastatic brain tumors depends on the extent of the patient's disease at presentation.  Patient's with a solitary brain metastatic tumor and relatively controlled systemic disease typically do best with surgical resection followed by whole brain radiation therapy to minimize recurrence and the development of additional metastatic tumors.  Patient's with greater than three intracranial metastases and relatively-advanced systemic disease are typically treated with whole brain radiation therapy alone.  Chemotherapy is often utilized for metastatic brain tumors as well, although many chemotherapy drugs have poor penetration into the central nervous system.  The ideal treatment algorithm for a patient with metastatic brain tumors is typically individualized and often developed by coordination between an oncologist, neurosurgeon, and radiation oncologist. Ft. Smith Neuroscience Center provides neurosurgical management for all types of brain tumors.

Fort Smith Neuroscience Center

Figure 2: MRI of a Glioblastoma multiforme.  Note the irregularity of the tumor, its large size, and the mass effect it is exerting on the surrounding brain