Clinical Presentations of Brain Tumors

Clinical Manifestations. Traditionally, headaches, nausea and vomiting, and papilledema constitute the clinical triad of increased intracranial pressure. Headaches resulting from elevated intracranial pressure are generalized in location and usually are worst upon awakening, occasionally even waking a patient from sleep. The vomiting is ascribed to pressure in the region of the fourth ventricle. Papilledema, or blurring of the optic disc margin due to swelling of the optic nerve (cranial nerve II) from the increased intracranial pressure, can be detected by ophthalmoscopic examination.

Local mass effect can result in a variety of neurologic symptoms, depending on what structures are affected. Symptoms may stem from local neural tissue invasion or compression of adjacent structures. Often, these focal signs and symptoms will manifest before the tumor enlarges to the point of causing increased intracranial pressure. Clinical presentations depend on the function of the affected tissue. In addition, headaches may also result from local mass effect. Typically, these headaches localize to the side of the tumor. They are usually dull and constant in character. Occasionally they may be severe. The combination of headaches associated with new neurologic abnormalities or changes in headache suggesting increased intracranial pressure should warrant consideration of an underlying neoplasm.

Seizures are another common sign that occur in association with an underlying malignancy. They can be either generalized or focal, with the focal seizures representative of the underlying location of the tumor. For example, distinct motor or sensory symptoms, such as weakness or numbness, relate to the functions of the cortical areas affected by the tumor. Cognitive changes may herald an underlying intracranial malignancy, especially if they are frontal in location. Often these changes are subtle, with patients experiencing fatigue, memory difficulties, personality changes, or apathy. Difficulties with balance or disequilibrium often occur when tumors arise in the posterior fossa. Visual field defects, such as a homonymous hemianopsia, may result from damage to the optic tracts, and bitemporal hemianopsia is often seen with compression of the optic chiasm by pituitary tumors. Occasionally, patients will be asymptomatic, but the physical examination may reveal subtle neurologic abnormalities, such as a drift of an upper extremity, asymmetric reflexes, or a positive Babinski sign.

Diagnostic Studies. Once suspicion is raised of an intracranial malignancy, neuroimaging is warranted. Gadolinium-enhanced magnetic resonance imaging (MRI) is the diagnostic modality of choice because it allows visualization of the tumor in relation to the surrounding brain parenchyma, especially in the posterior fossa. Computer tomography (CT) is still used in patients for whom magnetic resonance imaging (MRI) is contraindicated or in emergent situations where time is of essence. In addition, it is superior to MRI in the detection of bony involvement, particularly in the region of the skull base. Other imaging modalities include magnetic resonance spectroscopy (MRS), which analyzes the chemical composition of the area of interest in an effort to differentiate tumor from other abnormalities, and positron emission tomography (PET) with fluorodeoxyglucose (FDG), which detects metabolically active tumors. Finally, perfusion MRI has emerged as a potentially useful technique because it identifies areas of increased vascularity, which can be useful for planning of surgical removal.

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