Date post: | 07-Apr-2018 |
Category: |
Documents |
Upload: | howellalamo |
View: | 218 times |
Download: | 0 times |
of 32
8/3/2019 Oncologic Disorders of the Brain
1/32
ONCOLOGIC
DISORDERS OF THEBRAIN
8/3/2019 Oncologic Disorders of the Brain
2/32
BRAIN TUMORS
A brain tumor is a localized intracranial lesionthat occupies space within the skull.
Usually grow as a spherical mass, but they
can grow diffusely and infiltrate tissue.
8/3/2019 Oncologic Disorders of the Brain
3/32
PRIMARY BRAIN TUMORS
Originate from cells and structures within thebrain.
8/3/2019 Oncologic Disorders of the Brain
4/32
SECONDARY, OR METASTATIC,
BRAIN TUMORS
Develop from structures outside the brain.
8/3/2019 Oncologic Disorders of the Brain
5/32
CAUSE OF BRAIN TUMORS
Unknown
The only known risk factor is exposure toionizing radiation.
8/3/2019 Oncologic Disorders of the Brain
6/32
INCIDENCE
Have increased in the past few decades
The highest incidence of brain tumors in adultsoccurs in the fifth, sixth, and seventh decades,with a slightly higher incidence in men.
In adults, most brain tumors originate from glialcells (glial cells make up the structure and supportsystem of the brain and spinal cord) and aresupratentorial (located above the covering of thecerebellum). Neoplastic lesions in the brainultimately cause death by impairing vital functions,such as respiration, or by increasing intracranialpressure (ICP).
8/3/2019 Oncologic Disorders of the Brain
7/32
PATHOPHYSIOLOGY
Brain tumors may be classified into severalgroups:
Those arising from the coverings of the brain
(eg, dural meningioma), those developing in oron the cranial nerves (eg, acoustic neuroma),those originating within brain tissue (eg,
gliomas), and metastatic lesions originatingelsewhere in the body.
Tumors of the pituitary and pineal glands andof cerebral blood vessels are also types of
brain tumors.
8/3/2019 Oncologic Disorders of the Brain
8/32
GLIOMAS
Glial tumors, the most common type of brainneoplasm, are divided into many categories.
Astrocytomas are the most common type of
glioma.
Oligodendroglial tumors are another type ofglial tumor, representing 20% of gliomas
8/3/2019 Oncologic Disorders of the Brain
9/32
MENINGIOMAS
Represent 20% of all primary brain tumors, arecommon benign encapsulated tumors ofarachnoid cells on the meninges.
They are slow-growing and occur most often inmiddle-aged adults (more often in women).
Most often occur in areas proximal to the venoussinuses.
Manifestations depend on the area involved andare the result of compression rather than invasionof brain tissue.
Standard treatment is surgery with completeremoval or artial dissection.
8/3/2019 Oncologic Disorders of the Brain
10/32
ACOUSTIC NEUROMAS
Is a tumor of the eighth cranial nerve.
It usually arises just within the internal auditorymeatus, where it frequently expands before
filling the cerebellopontine recess.
May grow slowly and attain considerable sizebefore it is correctly diagnosed.
The patient usually experiences loss ofhearing, tinnitus, and episodes of vertigo andstaggering gait.
8/3/2019 Oncologic Disorders of the Brain
11/32
PITUITARY ADENOMAS
Represent about 8% to 12% of all brain tumorsand cause symptoms as a result of pressureon adjacent structures or hormonal changes
(hyperfunction or hypofunction of the pituitary).
8/3/2019 Oncologic Disorders of the Brain
12/32
Angiomas
Brain angiomas (masses composed largely of abnormalblood vessels) are found either in or on the surface of thebrain.
They occur in the cerebellum in 83% of cases.
Some persist throughout life without causing symptoms;others cause symptoms of a brain tumor.
Occasionally, the diagnosis is suggested by the presence ofanother angioma somewhere in the head or by a bruit (anabnormal sound) audible over the skull.
Because the walls of the blood vessels in angiomas are thin,these patients are at risk for a cerebral vascular accident(stroke). In fact, cerebral hemorrhage in people younger than40 years of age should suggest the possibility of an angioma.
8/3/2019 Oncologic Disorders of the Brain
13/32
CLINICAL MANIFESTATIONS
Brain tumors can produce either focal orgeneralized neurologic signs and symptoms.
Generalized symptoms reflect increased ICP,
and the most common focal or specific signsand symptoms result from tumors interferingwith functions in specific brain regions.
8/3/2019 Oncologic Disorders of the Brain
14/32
INCREASING ICP
EnlargingTumor
Disruption of the equilibrium that existsbetween the brain, the CSF, and the
cerebral blood, all located within theskull
As the tumor grows, compensatory
adjustments may occur.
Gradual compression of the
brain
8/3/2019 Oncologic Disorders of the Brain
15/32
compression of intracranial
reduction of CSF volume (by increasedabsorption or decreased production
a modest decrease of cerebral bloodflow, and reduction of intracellular and
extracellular brain tissue mass.
8/3/2019 Oncologic Disorders of the Brain
16/32
If compensatory mechanisms fail
Development of signs and symptoms
headache
Nauseaand
vomiting
6th
nervepalsy
Localize
dSympto
ms
8/3/2019 Oncologic Disorders of the Brain
17/32
Headache
Not always present
Most common in the early morning and is madeworse by coughing, straining, or suddenmovement.
It is thought to be caused by the tumor invading,compressing, or distorting the pain-sensitivestructures or by edema that accompanies thetumor.
Headaches are usually described as deep orexpanding or as dull but unrelenting.
Frontal tumors usually produce a bilateral frontalheadache; pituitary gland tumors produce painradiating between the two temples (bitemporal); in
cerebellar tumors, the headache may be locatedin the subocci ital re ion at the back of the head.
8/3/2019 Oncologic Disorders of the Brain
18/32
Vomiting
Seldom related to food intake
Usually due to irritation of the vagal centers inthe medulla.
8/3/2019 Oncologic Disorders of the Brain
19/32
Visual Disturbances and
Papilledema
Present in 70% to 75% of patients
Is associated with visual disturbances such asdecreased visual acuity, diplopia (double
vision), and visual field deficits.
8/3/2019 Oncologic Disorders of the Brain
20/32
Localized Symptoms
The most common focal or localizedsymptoms are hemiparesis, seizures, and
mental status changes When specific regions of the brain are
affected, additional local signs and symptoms
occur, such as sensory and motorabnormalities, visual alterations, alterations incognition, and language disturbances such asaphasia.
8/3/2019 Oncologic Disorders of the Brain
21/32
A motor cortex tumor produces seizure-like movementslocalized on one side of the body, called Jacksonian seizures.
An occipital lobe tumor produces visual manifestations:
contralateral homonymous hemianopsia (visual loss in half ofthe visual field on the opposite side of the tumor) and visualhallucinations.
A cerebellar tumor causes dizziness, an ataxic or staggeringgait with a tendency to fall toward the side of the lesion, marked
muscle incoordination, and nystagmus (involuntary rhythmiceye movements), usually in the horizontal direction.
8/3/2019 Oncologic Disorders of the Brain
22/32
A frontal lobe tumor frequently produces personality
disorders, changes in emotional state and behavior, and anuninterested mental attitude. The patient often becomesextremely untidy and careless and may use obscene
language.
A cerebellopontine angle tumor usually originates in thesheath of the acoustic nerve and gives rise to acharacteristic sequence of symptoms. Tinnitus and vertigo
appear first, soon followed by progressive nerve deafness(eighth cranial nerve dysfunction). Numbness and tinglingof the face and the tongue occur (due to involvement of thefifth cranial nerve). Later, weakness or paralysis of the face
develops(seventh cranial nerve involvement). Finally,because the enlarging tumor presses on the cerebellum,
ssessmen an agnos c
8/3/2019 Oncologic Disorders of the Brain
23/32
ssessmen an agnos cFindings
NeurologicExamination
CT Scan
indicates the areas of the CNSinvolved
gives specific information concerningthe number, size, and density of thelesions and the extent of secondary
cerebral edema, CT scans canprovide information about theventricular system.
8/3/2019 Oncologic Disorders of the Brain
24/32
MRI
- The most helpful diagnostic tool fordetecting brain tumors, particularlysmaller lesions A, and tumors in the
brain stem and pituitary regions,where bone interferes with CT.
- The appearance of a brain tumor
on an MRI is so characteristic that abiopsy is unnecessary, especiallywhen the tumor is located in a partof the brain that is difficult to biopsy.
8/3/2019 Oncologic Disorders of the Brain
25/32
Positron
emissiontomography
(PET)
-It is used to supplement MRI.-On PET scans, low-grade tumors areassociated with hypometabolism andhigh-grade tumors show
hypermetabolism.
8/3/2019 Oncologic Disorders of the Brain
26/32
Computer-
assistedstereotactic (3-dimensional)
biopsy
- Used to diagnose deep-seated braintumors and to provide a basis fortreatment and prognosis.
8/3/2019 Oncologic Disorders of the Brain
27/32
CerebralAngiography
- Provides visualization of cerebralblood vessels and can localize mostcerebral tumors
8/3/2019 Oncologic Disorders of the Brain
28/32
Electroencephalogram
- Can detect an abnormal brainwave in regions occupied by atumor and is used to evaluatetemporal lobe seizures and assist
in ruling out other disorders.
8/3/2019 Oncologic Disorders of the Brain
29/32
Cytologic Studies ofthe CSF - Detect malignant cells
8/3/2019 Oncologic Disorders of the Brain
30/32
Gerontologic Considerations
Produce personality changes, confusion,speech dysfunction, or disturbances ofgait.
The most frequent tumor types in theelderly are anaplastic astrocytoma,glioblastoma multiforme, and cerebral
metastases from other sites. The incidence of primary brain tumors and
the likelihood of malignancy increase with
age.
8/3/2019 Oncologic Disorders of the Brain
31/32
Medical Management
Chemotherapy
External-beam radiation therapy
Surgical resection
Intravenous (IV) autologous bone marrowtransplantation
Gene-transfer therapy
Photodynamic therapy
8/3/2019 Oncologic Disorders of the Brain
32/32
CHEMOTHERAPY
Antineoplastic agents