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