Pathology 4.4 Flashcards
Where are astrocytomas and other primary brain tumors typically found in adults?
cerebral hemispheres
Where are astrocytomas and other primary brain tumors typically found in children?
cerebellum
pons
What is the pertinent information about Glioblastoma Multiforme (GBM)?
40% of primary intracranial neoplasms
later decades in life
18 month prognosis
What are the gross findings of Glioblastoma Multiforme (GBM)?
infiltrates extensively in the cortex
- crosses corpus calloum
- bilateral extension into white matter of both hemispheres
mottled red (recent hemorrhage) mottled yellow (remote hemorrhage) **butterfly on gross examination
What are the histologic findings of Glioblastoma Multiforme (GBM)?
1) marked cellularity w/ variable degrees of:
- cellular pleomorphism
- multinucleated cels
- frequent mitoses (anaplasia)
2) serpentine areas ofnecrosis surrounded by zones of crowded tumor cells (peripheral palisading)
3) endothelial cell proliferation which creates clusters of small blood vessels (glomeruloid formations)
Where do oligodendriomas originate?
white matter
adult cerebral hemispheres
What are the histological findings of oligodendriomas?
- well-circumscribed
- gelatinous
- gray mass w/ cysts
- focal hemorrhage and calcifications
- sheets of cells with round nuclei
- clear halo of cytoplasm (“fried egg”)
How do patients with oligodendriomas present clinically?
- calcospherites (calcifications on radiography)
- seizures and several years of neurological complaints
Where is an ependymoma typically located and what is the symptomology?
fourth ventricle
hydrocephalus
Where are ependymomas most commonly found in the first two decades of life?
4th ventricle
Where are ependymomas typically found in adults?
spinal cord (filum terminale)
What are the most common tumors of the spinal cord?
1) astrocytoma
2) ependymoma
What are the gross features of ependymomas?
- solid or papillary mass
- extends from floor of 4th ventricle or intraspinal masses
- sharply demarcated from normal tissue
What are the histologic findings of ependymomas?
- sheets of cells with oval or round nuclei
- granual chromatin
- perivascular pseudorosettes
How do patients present clinically with ependymomas?
- hydrocephalus
- slow growing tumor, but can seed subarachnoid space with CSF dissemination
Which cancer is #1 in metastasizing to the brain?
1) melanoma
2) breast
3) lung
Why might a patient with an oligodendrioma have a seizure?
located in white matter
What are colloid cysts?
- located in 3rd ventricle
- round cysts most often occur in young adults
Where are colloid cysts typically located and what do they cause?
- roof of 3rd ventricle in mindline
- occlude Foramina of Monro
- cause hydrocephalus
How does a patient present with a colloid cyst?
- hydrocephalus
- headache
- lower leg weakness
- loss of bladder control
- idiopathic
What is the most common intracranial primitive neuroblastic tumor?
medulloblastoma; 20% of brain tumors in children
Where are medulloblastomas typically located?
exclusively in cerebellum
What are the histologic findings of medulloblastomas?
- small, round, hyperchromatic blue-cell tumors of children
- extremely cellular
- sheets of anaplastic cells
- scant cytoplasm
- rosette formation
- abundant mitoses
What are the gross findings of medulloblastomas?
- well-circumscribed
- gray
- friable
How do patients present clinically with medulloblastomas?
- cerebellar dysfunction
- hydrocephalus
- subarachnoid dissemination is common
What is the most common genetic alteration in a medulloblastoma?
-loss of material from short from of Ch 17
What are meiningiomas?
- intracranial tumors (20% of all) from arachnoid villi
- compress brain tissue
Where are meningiomas most commonly located?
- parasagittal areas
- convexities of cerebral hemispheres
- olfactory groove
- lateral wing of sphenoid
What is the most common genetic alteration in a meningioma?
deletion or mutation of Ch 22
How do meningiomas present grossly?
- well-circumscribed
- firm
- bosselated masses of variable size
-gray, fibrous pattern on cut section
What are the histologic findings of meningiomas?
- fibroblastic, whorled patternof “meningothelial” cells**
- Psammoma Bodies (laminated, spherical calcifications)
What is the clinical presentation of meningiomas?
- seizure + headache
- anosmia (@ olfactory groove)
- visual defects (suprasellar region)
What is a Schwannoma?
- benign neural crest tumor
- derived from Schwann cells
- “Neurilemmoma” or “neurinoma”
What does a CT of a meningioma show?
sharp demarcation from under-surface of dura
What are the gross findings of a Schwannoma?
- well-circumscribed
- encapsulated mass
- attached to nerves
What are the histologic findings of Schwannomas?
Antoni A pattern
-fascicles of elongated spindle cells
Antoni B pattern
-loosely staining, myxoid areas
What is an Acoustic Neuroma?
intracranial Schwannoma restricted to 8th CN
Where is an acoustic neuroma found?
cerebellar pontine angle
What is the clinical presentation of Acoustic Neuromas?
- tinnitus
- deafness
- compress other CNs
What is a Craniopharyngioma?
- solid and cystic lesions
- arise from epithelium of Rathke’s pouch
What is the Rathke’s pouch?
a part of the embryonic nasopharynx that migrates cephalad and gives origin to the anterior hypophysis
What is the clinical presentation of craniopharyngioma?
- slow-growing tumor
- childhood and adolescence
- 50% occur after 20 y/o
What are the gross findings of craniopharyngiomas?
- 3-4 cm
- > 3/4 contain sufficient calcification (seen on radiography)
How do children typically present with a craniopharyngioma?
- endocrine deficiencies (growth retardation)
- visual disturbance and headache in adults
What is the most common CNS neoplasm in patients with AIDS?
primary brain lymphoma; 1000 x’s greater in AIDS population than general public
What are the histologic findings of primary brain lymphomas?
- angiocentric distribution of small and large neoplastic lymphocytes
- B-cell origin
- EBV can be recovered in tumors of AIDS patients (etiology)
How do metastatic tumors reach the CNS?
- reach intracranial compartment through bloodstream
- generally in patients with advanced carcinoma
Where do most metastatic tumors to the brain seed?
gray-white matter junction
What is the pathophysiologic cause of seizure?
paroxysmal discharges from groups of neurons as a result of:
a. excessive excitation
b. loss of inhibition
* malfunction of ion channels*
What are the causes of seizure?
1/3 genetic
1/4 structural abnormalities
What is a seizure?
transient disturbance of cerebral function caused by abnormal neuronal discharges
What are the types of seizures anatomically?
partial/focal: affecs part of the brain
generalized: affects entire brain [Grand Mal Seizures]
What are the characteristics of generalized/clonic seizures?
1) sudden cry (diaphragmatic spasm)
2) fall
3) momentary rigidity
4) jerking of muscles, shallow breathing, cyanosis
(loss of bladder control)
What are the after-symptoms of a generalized/clonic seizure?
- confusion
- drowsiness
- fatigue
- memory loss
- unconsciousness
What is an absence seizure?
-type of generalized seizure
-most common in children and teens
[Petit Mal Seizure]
What are the characteristics of absence seizures?
- brief staring spells/blinking
- rapid return after 2-3 minutes
What are complex partial seizures?
1) visual sensation/aura
2) state of impaired consciousness, automatic motor activities, convulsions
What is the most common seizure in children and adults?
complex partial seizure
Where do complex partial seizures originate?
temporal lobe
What is hippocampal sclerosis?
- neuronal cell loss in Hippocampus
- segmental loss of pyramidal neurons and reactive gliosis
What is the most common type of neuropathologic damage in individuals w/ complex partial seizures?
hippocampal sclerosis
What is status epilepticus?
- recurrent convulsive or non-convulsive seizures
- full consciousness not restored between episodes
Is status epilepticus a medical emergency?
Yes; can result in:
- hyperthermia
- circulatory shock
- neuronal loss
- permanent brain damage
What is a febrile seizure?
- children 6 mo-5 y/o
- few minutes in length
- only occur with fever
What must be ruled out when a patient presents with a febrile seizure?
bacterial meningitis
-perform lumbar puncture
What are the most common lesions in generalized seizures?
- cerebral changes resulting from birth
- cerebral infarct
- brain tumor
- stroke
- AVMs
- trauma
What is the histology of seizures?
- neuronal loss
- gliosis
- loss of dendritic afferents (GABA-producing neurons)
- *lack of inhibition causes seizure
What are the clinical and physical findings of a seizure?
- normal temp unless infection
- elevated heart rate
- bp variable
- may be evidence of trauma
- postictal state if seizure is recent (confusion, drowsiness, behavioral changes)
What is a characteristic action of seizure disorder?
Tongue biting
