W/L CH: 30 Central Nervous System Tumors

CNS tumor grading scale

-1 = benign tissue, cells look nearly like healthy brain cells, grows slowly -2 = tissue malignant, cells looks less like healthy cells than do the cells in a grade 1 tumor -3 = malignant tissue has cells that look very different from healthy cells, abnormal cells are actively growing (anaplastic) -4 = malignant tissue has cells that look most abnormal and tend to grow quickly

ependymal cells

-line choroid plexuses -responsible for secreting ~0.5 L of cerebral spinal fluid each day into ventricles

lymphocyte and microglia

-lymphoma -part of immune system -body's primary defense against infection and foreign substances -microglial cells support neurons and phagocytize bacteria and cellular debris

primitive neuroectodermal cells (PNETs)

-medulloblastoma -cells comprise a family of small blue round cell mass and are most common malignant nervous system tumors of childhood -cells don't usually remain in body after birth

meninges

-meningioma -comprised of 3 distinct coverings that protect brain and spinal cord -CSF circulates within meninges

brainstem or thalamus tumors

-symptoms = nausea, vomiting, ataxia -signs = increased intracranial pressure (papilledema) abducens and oculomotor nerve defects, coordination -diagnostic characteristics = may not enhance CT, biopsy may not be appropriate

cerebellar tumors

-symptoms = occipital headache -signs = increased intracranial pressure (papilledema), abducens and oculomotor nerve defects, coordination

optic nerve tumors

-symptoms = ocular symptoms -signs = ocular changes -diagnostic characteristics = detailed MRI or CT scan

Karnofsky performance status (KFS) is:

a measure of the neurologic and functional status of the patient

Little is known concerning the _________, development, and growth mechanisms of CNS tumors.

etiology

The most common brain lesion is:

glioma

T/F: The most important prognostic factor for CNS tumors is the histopathologic diagnosis.

true

Cells are more radiosensitive when they are:

well oxygenated

CNS tumor facts

-1.4% of all malignancies -80% involve brain, 20% involve spinal cord -second leading cause of cancer death in children -glioma most common type (30% of all CNS tumors, 80% of malignant brain cell tumors, 45% of childhood tumors - usually involve cerebellum) -20-40% of cancers have brain mets -30-60% of lung cancer patients get brain mets, usually in cerebral hemispheres

Schwann cells

-Schwannoma -produce a fatty insulating substance called myelin, which insulates and protects nerves outside CNS

CNS neoplasm chemo

-carmustine -procarbazine -vincristine -lomustine -temozolomide (malignant gliomas)

ventricles

-cavities that form a communication network with each other, the center canal of spinal cord, and subarachnoid space -lateral ventricles = located below corpus callosum and extend from front to back; opens into 3rd ventricle; communicates with 3rd ventricle via interventricular foramen -4th ventricle = between cerebellum and inferior brainstem

cerebrospinal fluid (CSF)

-clear, colorless fluid resembling water -CNS contains 3-5 oz -composed of proteins, glucose, urea, and salts -protects brain via buoyancy, helps control chemical environment of CNS, means of exchanging nutrients and waste products with CNS, channel for intracerebral transport

spinal cord

-continuation of medulla oblongata -forms inferior portion of brainstem -anterior and lateral portions contain motor neurons and tracts -posterior portion contain sensory tracts

What provides protection for the brain?

-cranial bones -meninges -CSF

craniospinal axis radiation treatment

-encompasses entire brain and spinal cord simultaneously -commonly used to treat medulloblastoma, sometimes used to treat germ cell tumors and ependymoma with distant CNS mets -treated prone -2 lateral whole brain fields and 1+ posterior spinal field(s) -no overlap, feathering used by shifting gap 1 cm every 1000 cGy (1 cm gap between fields daily)

ependyma

-ependymoma -cells that line ventricles and spinal cord -cuboidal shaped -aid in production and circulation of cerebrospinal fluid

What are some important factors to consider in the initial workup for a definitive diagnosis of CNS neoplasm?

-family and social histories -changes in behavior or personality -difficulties with speech, memory, or logical thought processes

tentorium

-fold of dura mater or outer covering of brain -separates cerebral and cerebellar hemispheres

clinical manifestations of spinal cord tumors

-foramen magnum = 11th and 12th cranial nerve palsies; ipsilateral arm weakness early; cerebellar ataxia; neck pain -cervical spine = ipsilateral arm weakness with leg and opposite arm in time; wasting and fibrillation of ipsilateral neck, shoulder girdle, and arm; decreased pain and temperature sensation in upper cervical regions early; pain in cervical distribution -thoracic spine = weakness of abdominal muscles; sparing of arms; unilateral root pains; sensory level with ipsilateral changes early and bilateral with time -lumbosacral spine = root pain in groin region and sciatic distribution; weakened proximal pelvic muscles; impotence; bladder paralysis; decreased knee jerk and drink ankle jerks -cauda equina = unilateral pain in back and leg, becoming bilateral when tumor is large; bladder and bowel paralysis

cranial nerve functions of brain tumors

-frontal = anosmia (inferior lesion); nerve 6 palsy with increased ICP; papilledema with increased ICP; Foster Kennedy syndrome; proptosis -parietal = hemianopsia; papilledema with increased ICP -temporal = superior quadrantanpsia (X; could be homonymous hemianopsia with tumor extension); central weakness of cranial nerve 6; papilledema with increased ICP -occipital = macular-sparing hemianopsia; horizontal nystagmus

special cerebral functions of brain tumors

-frontal = behavioral problems (anterior location); labile personality; mental lethargy; defective memory; motor aphasia -parietal = anosognosia; autotopagnosia; visual agnosia; graphesthesia; memory loss; proprioceptive agnosia -temporal = dysarthria; sensory aphasia; defective hearing -occipital = visual agnosia; visual impulses

motor system of brain tumors

-frontal = contralateral weakness (late); paresis (flaccid spastic); disturbed gait (midline lesion); automatism; persistence of induced movement (Kral's phenomenon); diagonal rigidity (arm [X]; leg [-]); loss of skilled movement (X); urinary incontinence (super lesion) -parietal = weakness; atrophy; clumsiness; dysdiadochokinesia; independent movements (unrecognized by patient) -temporal = dysdiadochokinesia (early); drift (secondary in later stages, involving arm more than leg) -occipital = late appearance of motor signs, manifested by drift or dysdiadochokinesia

brain tumor location symptoms

-frontal = often asymptomatic until late; increased ICP; bradyphrenia; personality changes; libido changes; impetuous behavior; excessive jocularity; defective memory; urinary incontinence; seizures (generalized, becoming focal); gait disorders; weakness; loss of smell; speech disorder; tonic spasms of fingers and toes -parietal = symptomatic early than frontal lobes; symptoms of increased ICP; loss of vision; spatial disorientation; tingling sensation; dressing apraxia; memory loss; seizures (focal sensory epilepsy); weakness (anterior extension) -temporal = speech disorders (left hemisphere dominant, not only for right-handed but for most left-handed people); loss of smell (superior lesions); disturbance in hearing, tinnitus; speech disturbance; uncinate fits; seizures with vocal phenomena in aura, including speech arrest; hallucinations, dreams, deja vu; space-perception disturbances; dysarthria; dysnomia; disturbance of comprehension -occipital = seizure s(relatively less common but with aura, including flashing lights with unformed hallucinations); vision loss; tingling (early); weakness (late)

sensory functions of brain tumors

-frontal = rare involvement initially, unless invasion of sensory area (posterior lesion) -parietal = dysesthesias (tingling; X); pallesthesia (loss of vibratory sense; X); loss of touch, press and position sense (X), but pain and temperature are usually unaffected -temporal = initially minimal -occipital = somatosensory disturbances earlier than motor changes as adjacent structures are involved; visual phenomena, such as persisting images, unformed hallucinations, and aura

reflex changes in brain tumors

-frontal = tonic plantar reflex; Hoffmann's sign; grasp reflex; Babinski's sign -parietal = Babinski's sign; Hoffmann's sign -temporal = may occur contralateral to tumor -occipital = no effect in early stages

cerebrum

-functions: interpretation of sensory impulses and voluntary muscular activities -center for memory, learning, reasoning, judgment, intelligence, and emotions

astrocytes

-glioma (glioblastoma, astrocytoma, glioblastoma multiforme, brainstem, and thalamus tumors) -star-shaped cells found between neurons and blood vessels that provide support and help regulate ions -important part of blood-brain barrier

gray and white matter

-gray matter = 40% of CNS; contains supportive nerve cells and related processes; forms cortex/outer part of cerebrum; surrounds white matter -white matter = 60% of CNS; composed of bundles of nerve fibers, axons that carry impulses away from cell body, and dendrites that carry impulses towards cell body

The purpose of the BBB is to:

-hinder the penetration of some substances into the brain and CSF -protect the brain from potentially toxic substances

blood-brain barrier (BBB)

-hinders penetration of some substances into brain and CSF -exists between vascular system and brain -protects brain from potentially toxic compounds -substances that do pass through must be lipid soluble (alcohol, nicotine, heroin) -water-soluble substances (glucose, some amino acids, sodium) need a carrier molecule to cross barrier via active transport

whole brain radiation therapy

-inferior field margin = superior orbital ridge to mastoid tip -1 cm of flash on anterior, posterior, and superior field borders -palliative dose = 3000-3750 cGy in 10-15 fractions (250-300 cGy per fraction)

patterns of CNS tumor spread

-most gliomas spread through local invasion; they don't form a capsule that inhibits growth; rarely metastasize outside of CNS -tumor cells may break off and circulate within CSF -medulloblastomas and primitive neuroectodermal tumors tend to seed via CSF into spinal and intracranial subarachnoid spaces -drop metastasis -> when secondary tumors are formed via CSF -secondary seeding -> growth along nerve roots, causing pain or cord compression; lumbosacral region most common

CNS tumor risk factors

-occupational and environmental = chemicals, synthetic rubber, pesticides, herbicides, ionizing radiation, electromagnetic fields; agriculture and healthcare workers -lifestyle = cell phones, nitrates, hair dye, smoking -medical = drugs, viral infections, AIDS -genetic = neurofibromatosis, tuberous sclerosis, Li-Fraumeni syndrome, von Hippel-Lindau syndrome; increased risk when close relative diagnosed with glioma

oligodendrocyte

-oligodendroglioma -smaller cells that resemble an astrocyte -produces a fatty insulating substance called myelin. which may be provided to many nearby axons

intracranial pressure (ICP)

-pressure that occurs within cranium -increased ICP can cause headaches, vomiting, lethargy, seizures, and neurologic symptoms -can be caused by interruption in flow of CSF

Karnofsky Performance Scale

-scale that measures the neurologic and functional status -allows measuring of the quantity and quality of neurologic defects -scale ranges from 1-100 -higher score means patient is better able to carry out daily activities

benign/malignant oligodendroglioma

-signs = insidious headache, mental changes -symptoms = focal presentation related to tumor location -diagnostic characteristics = radiographic calcification

benign/malignant pituitary tumors

-signs = vertex headache, ocular changes -symptoms = ocular and endocrine abnormalities -diagnostic characteristics = hormone analysis, resection histopathology

supratentorial and infratentorial regions

-supratentorial = includes cerebral hemispheres, the sella. pineal, and upper brainstain region -infratentorial = leads to upper spinal cord, houses brainstem, pons, medulla, and cerebellum

papilledema

-swelling of the optic disc -results from increased ICP

benign/malignant hemangioma, arteriovenous malformation

-symptoms = "migrainous" headache -signs = focal presentation related to tumor location -diagnostic characteristics = angiography, biopsy may not be appropriate

malignant sarcoma and benign neurofibroma

-symptoms = focal presentation related to tumor location -signs = focal presentation related to tumor location

malignant lymphoma, reticulum cell sarcoma, microglioma

-symptoms = focal presentation related to tumor location -signs = focal presentation related to tumor location -diagnostic characteristics = "soft" CT enhancement

craniopharyngioma

-symptoms = headache, mental changes, hemiplegia, seizure, vomiting, ocular changes -signs = cranial nerve defects (2-7) -diagnostic characteristics = cystic/calcified lesion on MRI; bone erosion, mass effect from base of skull

cerebral tumors

-symptoms = headache, seizure, unilateral weakness, mental changes -signs = focal presentation related to tumor location

malignant astrocytoma, glioblastoma multiforme, astrocytoma with anaplastic foci

-symptoms = headache, seizure, unilateral weakness, mental changes -signs = focal presentation related to tumor location -diagnostic characteristics = enhancing CT lesion, tumor blush on angiography (malignant astrocytoma); CT lesion (glioblastoma multiforme); no hypodense interior enhanced MRI or CT lesion (astrocytoma with anaplastic foci)

benign/malignant astrocytoma

-symptoms = headache, seizure, unilateral weakness, mental changes -signs = focal presentation related to tumor location -diagnostic characteristics = may not enhance on CT or MRI

benign/metastatic meningioma

-symptoms = localized headache, seizure -signs = focal presentation related to tumor location -diagnostic characteristics = enhancing MRI or CT lesion associated with dura

benign/metastatic ependymoma

-symptoms = morning headaches, nausea, vomiting -signs = coordination, increased intracranial pressure (papilledema), abducens and oculomotor nerve defects -diagnostic characteristics = MRI or CT scan, lumbar puncture recommended

metastatic medulloblastoma

-symptoms = morning headaches, nausea, vomiting -signs = coordination, increased intracranial pressure (papilledema), abducens and oculomotor nerve defects -diagnostic characteristics = MRI or CT scan, lumbar puncture recommended

benign/malignant pinealoma and germinoma

-symptoms = various (ocular, vestibular, endocrine) -signs = parinaud syndrome, endocrine changes, ocular changes, increased intracranial pressure, abducens and oculomotor nerve defects -diagnostic characteristics = biopsy or resection may not be obtained; markers in CSF may be informative

Surgery for CNS neoplasms can be limited by:

-tumor location and extent -patient status -risk of causing neurologic deficits

CNS radiation tolerances

-whole brain = 4500-5000 cGy -partial brain = 6000 cGy -spinal cord = 4500-5000 cGy

radiosensitizer

chemicals that enhance lethal effects of radiation

cerebellum

part of brain that plays role in coordination of voluntary muscular movement