Central nervous system tumors cause either focal or generalized neurologic symptoms.

Epidemiology

• Incidence - ~41,000 new cases of primary brain tumors are diagnosed yearly in the U.S.
  • Half are histologically benign
• Gender - F slightly >M
  • Higher meningioma incidence in females

Risk factors

• Ionizing radiation (gliomas)
• Familial
  • Neurofibromatosis 1 (NF-1), (neurofibroma, glioma, sarcoma)
  • Neurofibromatosis 2 (NF-2a), Schwannoma glioma, meningioma
  • Tuberous sclerosis (astrocytoma)
  • Von Hippel-Lindau (hemangioblastoma)
  • Li Fraumeni (glioma)
  • Retinoblastoma
  • Multiple endocrine neoplasia 1 (pituitary adenoma, Schwannoma glioma)
• Virus infection
  • HIV infection is associated with an increased risk of CNS lymphoma

Pathophysiology

• Histologically classified as glioma or nonglioma
  • Gliomas
    • Astrocytomas (includes glioblastoma multiforme)
    • Oligodendrogliomas
    • Mixed gliomas
    • Ependymomas
  • Nongliomas
    • Meningiomas - usually benign
    • Pituitary adenomas - often benign
    • Primary CNS lymphoma
    • Medulloblastoma - childhood cerebellar tumor
    • Brain metastases - lung, breast and melanoma are most common
• Malignant gliomas are the most common type of primary brain tumor
• Separation of astrocytomas from oligodendrogliomas has prognostic and therapeutic importance

Clinical Presentation

• Headache, nausea, vomiting, hemiparesis, aphasia
• Seizures - more common with gliomas

Diagnosis

• Laboratory testing
  • Very few abnormalities except for increased erythrocyte sedimentation rate (ESR)
• Imaging studies
  • CT, MRI, PET
• Markers
  • Combined loss of short arm of chromosome 1 (1p) and long arm of chromosomes 19 (19q) is considered a diagnostic and prognostic marker of oligodendrogliomas
    • Patients with 1p and 19q deletions have a better prognosis than those without the deletions
    • Loss of 1p may identify treatment-sensitive malignant gliomas, in particular, subtypes of anaplastic oligodendroglioma