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CNS TUMORSCNS TUMORSAlina Valdes, M.D.

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Devastating effects High mortality rates Benign tumors may be unresectable so

incurable Malignant if cannot be removed completely Incidence increases with advancing age after

childhood, when second most common cancer No environmental agent known to be causative

except for vinyl chloride with gliomas and CNS radiation with several tumors

No evidence supports viral origin

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ClassificationClassification World Health Organization classification

Primary tumors classified on basis of cell origin Most primary tumors of neuroepithelial origin

From malignant transformation of astrocytes, ependymocytes, and oligodendrocytes

Gliomas most common Arise from astrocytes

Metastases more likely than primary CNS tumor in patient with known systemic malignant disease

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Clinical ManifestationsClinical Manifestations Symptoms from intracranial tumors

Compression of brain by tumor and presence of associated edema

Infiltration and destruction of brain parenchyma by tumor cells

Rigid cranial cavity so benign and malignant tumors may cause symptoms

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Symptoms from primary brain tumors slowly progressive

Symptoms from metastatic tumors more acute Grow more rapidly and associated with

edema Hemorrhage into tumor

May present with generalized symptoms from increased intracranial pressure or focal symptoms from areas of compromise

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Generalized symptoms Headache

Most common generalized symptom and first in ½ of adults

Infrequently from tumor itself but rather from increased intracranial pressure

Changes in mood or personality Decrease in appetite Nausea Projectile vomiting – in children Generalized or focal seizures – in 20% of

patients

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Focal symptoms Frontal lobe tumors

May be massive before symptoms cause problems

Progressive difficulty with concentration and memory, personality changes, and lack of spontaneity

Urinary incontinence and gait disorderAppearance of primitive reflexes in bifrontal

disease

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Parietal lobe tumorsSubtle signs or more dramatic like hemianesthesia

Right: spatial disorientation or left homonymous hemianopia

Left: receptive aphasia or right homonymous hemianopia

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Temporal lobe tumorsPersonality changes, auditory hallucinations, complex partial seizures, and quadrantanopia

Uncal herniation if large enoughMetastatic spread of primary CNS

tumors to sites outside CNS rareSpread to meninges and spinal cord

occurs with most malignant CNS tumors

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Patient EvaluationPatient Evaluation Careful neuro exam Contrast-enhanced CT scan or MRI

MRI superior More useful in imaging posterior fossa More sensitive in detecting parenchymal invasion

CT scan without contrast not adequate for primary or metastatic tumors

Cerebral angiography only when tumor blood supply needed prior to resection

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Biopsy Accurate histological diagnosis Detect other disease like abscess Open craniotomy or MRI-guided or CT-

guided stereotactic techniques In 20% of patients with metastatic tumors,

CNS biopsy helpful in identifying primary site Lumbar puncture

Helpful only if suspect leptomeningeal involvement

Contraindicated when intracranial mass lesion present

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TreatmentTreatment Surgery

Most patients with primary tumors Many patients with solitary brain metastasis May relieve symptoms for many months if debulk

tumor when surgical cure unlikely No extensive resection with brain stem tumors Radical resection not recommended for tumors in

language or sensorimotor areas, basal ganglia, or corpus callosum due to neuro dysfunction

Not recommended for CNS lymphoma: multifocal and respond to chemo and radiation combination

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Increased intracranial pressure Most patients have brain edema and benefit

from glucocorticoids, usually dexamethasone

In life-threatening edema with signs of herniation, can give mannitol with dexamethasone

Anticonvulsants Given if develop seizures Given if at risk of developing seizures before

performing biopsy or surgery: many patients don’t need postoperatively

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Radiation1. Conventional – external beam

• Uses direct X-rays to whole-brain or focal area

• Whole-brain radiation associated with long-term toxicity, like dementia and gait disturbance

2. Brachytherapy• Implantation of permanent or temporary

radiation “seeds” within tumor• Allows higher doses to tumor while

preserving normal tissue

3. “Radiosurgery”• Converging more than 200 beams of

radiation onto small, well-defined tumors

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Chemotherapy Not used as sole therapy Major obstacle is blood-brain barrier CNS tumors often drug resistant Biodegradable wafers impregnated with

nitrosurea BCNU placed into tumor after resection

Oligodendrogliomas unusually sensitive CNS lymphomas treated with combination

chemo and radiation

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Malignant AstrocytomasMalignant Astrocytomas Group of heterogeneous tumors:

glioblastoma multiforme, anaplastic astrocytoma, and anaplastic oligodendroglioma

Glioblastoma multiforme Worst prognosis with median survival <12

mos. Surgery and radiation to improve symptoms

and quality of life If relapse, benefit of treatment short-lived

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Anaplastic astrocytoma and anaplastic oligodendrogliomaMedian survival of 4 to 5 yearsOligodendroglioma or mixed benefit

most from chemo after surgeryRecurrent treated same as

glioblastoma multiforme

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Glioma involving most of the left parietal lobe – seen to the right on this axial CT scan (arrow). The appearance is of a cystic tumor, but biopsy and histological confirmation are necessary to be certain of its nature.

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Cystic glioblastoma of the brain stem (arrowed), clearly demonstrated by MRI. The sagittal section shows that the tumor involves the posterior part of the brainstem and extends into the cerebellum.

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MeningiomasMeningiomas Arise outside brain Generally grow slowly Benign in 90% of cases Complete resection should be attempted Risk of recurrence proportionate to extent

of resection If partial resection, give postop radiation If malignant, radiation given Chemotherapy not used

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Meningioma in the occipital lobe, as revealed on contrast-enhanced CT scan. The patient presented with a contralateral homonymous hemianopia.

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CT scan showing a right frontal meningioma with a vascular capsule. The contrast-enhancement technique used in this scan demonstrates the classic appearance of a densely enhancing, sharply marginated tumor, tightly against the dura.

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MRI picture of a right frontal meningioma (same patient as in slide 21). MRI shows the fissures of the brain more clearly than CT; it shows the tumor well, and parts of its vascular supply appear as hypodense images (arrows).

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MRI sagitttal view of the patient seen in slides 21 and 22. This view demonstrates the relationship of the meningioma to the dura and skull very clearly, and shows the vascular capsule posteriorly (arrow).

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CNS LymphomaCNS Lymphoma Increasing in incidence No evidence of lymphoma outside CNS if

primary Most often occur deep in frontal lobe so

less likely to present with seizures than other primary and metastatic CNS neoplasms

Presenting complaints – headache, personality changes, and focal symptoms

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40% of immunocompetent and nearly 100% of AIDS patients have multifocal lymphoma when diagnosed

>40% of patients have leptomeningeal involvement – rarely symptomatic

20% of patients have involvement of one or both eyes

May be confused with metastatic disease since often multifocal

Surgical resection not indicated

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Treatment Corticosteroids: cytotoxic effects on

lymphoma cells; not sufficient Combination of systemic chemotherapy

before whole-brain radiation 5-year survival rates with combined

therapy as high as 30% If complete response to chemotherapy,

may defer radiation due to associated late effects

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Metastatic Tumors to the BrainMetastatic Tumors to the Brain Comprise most of intracranial tumors Common: lung, breast, and melanoma Present with headache, seizures, focal

symptoms, depression, and changes in mental status

Metastases usually multifocal Rapidly growing tumors can cause

massive edema

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Treatment Corticosteroids – dexamethasone in

brain edema Radiation Surgery possible if solitary or easily

resectable and systemic disease well controlled

Not usually respond to chemotherapy because of blood-brain barrier

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Multiple cerebral metastases in a patient with carcinoma of the breast, demonstrated on CT scan. Axial ‘cuts’ at other levels in the brain demonstrated further lesions.

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Spinal Cord TumorsSpinal Cord Tumors Much less common than brain Extradural or intradural

Most extradural are metastasis from other sites

Intradural described as Extramedullary: arising outside spinal cord, e.g.

schwannomas and meningiomas Intramedullary: arising within spinal cord, e.g.

ependymomas and astrocytomas Most common location is thoracic area

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Symptoms usually from compression of normal structures or compromise of blood supply not invasion of parenchyma

Early symptoms are back pain and distal paresthesias; then loss of sensation and weakness below level of tumor and loss of bowel and bladder control

MRI most useful and mostly replaced myelography

Urgent evaluation if progressive deficits

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Treatment with surgical resection High-grade astrocytoma followed by

radiation Epidural metastasis treated with high

doses of corticosteroids and surgery or radiation

Surgical decompression if acute onset of symptoms or if pathology not known

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Subdural lipoma demonstrated by MRI in sagittal section. The lipoma (large arrows) is severely compressing the spinal cord (small arrows).