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INTRODUCTION

APPROACH TO THE PATIENT: Tumors of the Nervous System

Clinical Presentation: Brain tumors of any type can present with general and/or focal symptoms and signs. General nonspecific symptoms include headache with or without nausea and vomiting, cognitive difficulties, personality change, and gait disorder. The classic headache associated with a brain tumor is most evident in the morning and improves during the day, but this pattern is actually seen in only a minority of pts. Papilledema may suggest elevated intracranial pressure. Focal symptoms and signs include hemiparesis, aphasia, or visual field deficit; these are typically subacute and progressive. Seizures are a common presentation, occurring in about 25% of pts with brain metastases or malignant glioma.

Evaluation: Primary brain tumors, unlike metastases, have no serologic features of malignancy such as an elevated ESR or tumor-specific antigens. Cranial MRI with contrast is the preferred diagnostic test for any pt suspected of having a brain tumor; CT should be reserved for pts unable to undergo MRI. Malignant brain tumors typically enhance with contrast and may have central areas of necrosis; they are characteristically surrounded by edema of the neighboring white matter. Low-grade gliomas typically do not enhance. Additional testing such as cerebral angiogram, EEG, or lumbar puncture is rarely indicated or helpful.

TREATMENT: TUMORS OF THE NERVOUS SYSTEM SYMPTOMATIC TREATMENT

  • Glucocorticoids (dexamethasone 12–16 mg/d in divided doses PO or IV) to temporarily reduce edema

  • Anticonvulsants (levetiracetam, topiramate, lamotrigine, valproic acid, or lacosamide) for pts who present with seizures; there is no role for prophylactic anticonvulsant drugs

  • Low-dose SC heparin for immobile pts

DEFINITIVE TREATMENT
  • Based on the specific tumor types and includes surgery, radiotherapy (RT), and chemotherapy

PRIMARY INTRACRANIAL TUMORS

Astrocytomas

Infiltrative tumors with a presumptive glial cell of origin. Most common primary intracranial neoplasm. Only known risk factors are ionizing radiation and uncommon hereditary syndromes (neurofibromatosis, tuberous sclerosis). Infiltration along white matter pathways often prevents total resection. Imaging studies (Fig. 189-1) fail to indicate full tumor extent. Grade I tumors (pilocytic astrocytomas) are the most common tumor of childhood, typically in the cerebellum; can be cured if completely resected. Grade II astrocytomas usually present with seizures in young adults; if feasible should be surgically resected. RT is helpful and chemotherapeutic agents such as temozolomide are increasingly used. Grade III (anaplastic astrocytoma) and grade IV (glioblastoma) astrocytomas are treated similarly with maximal safe surgical resection followed by RT with concomitant temozolomide, followed by 6–12 months of adjuvant temozolomide. Median survival in glioblastoma is 12–15 months. Glioblastomas invariably recur, and treatment options include reoperation, carmustine wafer implantation, and chemotherapeutic regimens including bevacizumab. The most important adverse prognostic factors in high-grade astrocytomas are older age, histologic features of glioblastoma, poor performance status, and unresectable tumor.

FIGURE 189-1

Postgadolinium T1 MRI of a large cystic left frontal glioblastoma.

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