classification diagnosis of brain tumors

8/12/2019 Classification Diagnosis of Brain Tumors

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Classification and Diagnosis of

Brain Tumors

T omas L. E s, M.D.

September 1, 1999


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CNS Tumors WHO Classification(1979)

Tumors of Neuroepithelial Tissue

strocyt c umors

Astrocytoma, Anaplastic Astro, GBM

ocy c as rocy oma

Pleomorphic xanthoastrocytoma

Oligodendroglial tumors

Ependymoma

M xo a illar e end moma

Subependymoma


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CNS Tumors WHO Classification(1979)

Cysts and tumor-like lesions

a e s c e cy s

Epidermoid, dermoid

Colloid c ts

Neurenteric cyst

LipomaPituitary Tumors

Local Extensions from Regional Tumors

ran op aryng omaParaganglioma

Metastases


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CNS Tumors Dia nosis

Clinical Ra ograp c

a ora ory


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CNS Tumors - Clinical Diagnosis

Headaches

Presentin s m tom in 35% ultimatel 70%

Generally dull and non-throbbing

Harbinger features:

Wake the patient at night

Worse on waking, improve throughout day

Exacerbated by exercise, coughing, posturalchange


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Seizures

resent ng sx n o pat ents w t ra n tumors

Occurs at some stage of the illness in 50-70%

Half are focal motor, half generalized

Tumors located near central sulcus more epileptogenicAbout 10-20% of adults with new onset seizures have

brain tumors

Patients with malignant gliomas who present withseizures tend to have a better prognosis


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Localizing Symptoms and Signs

Parietal Lobe

Sensory lossJoint sense,two-point discrim, stereognosis,graphesthesia

Dominant acalculia,finger agnosia, L-R confusionon- om nan anosagnos a

Hemiparesis, field cut, apraxia,

cc p a o eHomonymous hemianopsia

sua agnos as, aprosopagnos a, a n s syn rome


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Brain Stem

Cranial neuropathies, weakness, numbness,ataxia, verti o, hiccu s

Can produce hydrocephalus

Vermis truncal ataxia

Hemisphere appendicular ataxiaHydrocephalus not uncommon

Nystagmus, hypotonia


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Pineal Re ion

Midbrain compression Parinauds

Precocious puberty

r en r c e

Hypothalamic dysfunction

Autonomic dysfunction

Hydrocephalus

Diabetes insipidus


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CNS Tumors - Radiographic Diagnosis

Skull X-rays

Rarel necessar but can detect calcification

Astrocytomas are most common calcifying tumorOther tumors that calcif

Craniopharyngioma

OligodendrogliomaEpendymoma

Ganglioglioma

MeningiomaPituitary tumors produce eroded sella

Meningiomas may produce hyperostosis


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Will detect >90% tumors

Small pituitary tumors

Brain stem tumors

Low rade astroc tomas

Small metastases

Contrast ma hel distin uish:

Isodense lesion from surrounding parenchyma

Hypodense lesion from surrounding edema


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MRI

More sensitive than CT for ickin u small

tumorsProvides much reater anatomic detail es . for

Skull base

Posterior fossa

intracranial vessels

hemorrhage


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Angiography

o onger use rou ne y or agnos s o

brain tumors

Role limited to:

Preoperative eval of vascular anatomyAssessment of patency of venous sinues

Ruling out AVM or aneurysm in

pa en s w o presen w emorr age


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Positron Emission Tomography

Based u on the rinci le of annihilation coincidence

detectionQuantitative measurement of lucose metabolism

can be used to determine tumor grade

Can also be used to measure blood flow, pH, oxygenutilization, and amino acid metabolism

Can also be used to distinguish between tumor recurrence

and radiation necrosisUse is limited by cost and by the need for a

cyclotron to produce the isotopes


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Single Photon Emission Computed Tomography

radiopharmaceuticals which are taken up by brainand emit photons detected by rotating camera.

Images resemble those of PET scan except that SPECT

images only blood flowem -quan a ve es ma on o racer up a e s aseupon measuring counts/pixel in ROI on screen

,recurrent tumor from radiation necrosis

Much less ex ensive, widel available


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CNS Tumors Laboratory Diagnosis

er me ryVisual fields can be assessed by:

Goldmann kinetic perimetry

Humphries static perimetry

Important in evaluating pituitary tumors

Useful for:Confirming deficits found on exam

Detecting subtle deficits not found on exam

Monitoring effects of treatment


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EEG

Large tumors producing mass effect and tumors involving

the diencephalon may produce asynchronous

generalized slowing

L m te va ue as a screen ng test.

Evoked PotentialsBSAEPs abnormal in >90% of pts with CN VIIIth tumors

Most reliable indication of compression:

Prolongation of wave I-III and I-IV interpeaklatency

EPs more useful for intraoperative monitoring


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Cerebrospinal Fluid Analysis

LP contraindicated in many pts with brain tumorsCytology may be useful in pts with suspected

lymphoma

Important in post-operative staging of patientswith medulloblastoma

Can be useful in diagnosis of neoplastic

meningitisSometimes helpful in diagnosis of germ cell

tumors


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AFP HCG PLAP

GerminomaTeratoma

- +/- +- - +/-

Choriocarcinoma

Yolk Sac Tumor

- + +/-

+ - +/-

Embryonal Cell + + +/-

- - -

Pineoblastom - - -


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u ome ry

Useful screening test for CPA tumors

some sensorineural hearing loss on pure tone

Most common pattern:

g requency ear ng ossReduced speech discrimination


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Endocrine Evaluation

tumors

nvo ves measuremen o ormona eve s n

blood and urine and dynamic testingAt some institutions, may include sampling

of venous sinuses for tumor localization


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Vestibular Schwannoma

Account for 10% of all brain tumors , ,

common presentation

and hyperintense on T2 weighted images

t contrast, tumors as sma as mm areoften detectable


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Craniopharyngioma

Most commonly found in patients 5-10ears of a e

Usually present with headache, N/V,visual

, ,disturbance

, ,cystic mass

y rocep a us common y present


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Glioblastoma

Median age 50-60 Sli ht male re onderance

Variable presentation; seizures, headaches

-extensive edema

signal on T2

enhance


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Low Grade Astrocytomas

Usually occur in adults and may presentwith seizures headaches ro ressive

neurologic deficit

- ,lesion with little surrounding edema

,

T2


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classification diagnosis of brain tumors

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