CNS Tumors Flashcards
Where do most adult CNS tumors occur?
in cerebral hemispheres, most freq in frontal lobes
Where do most childhood CNS tumors occur?
posterior fossa
List some key general features of astrocytomas
most common glial tumor
80% are glioblastomas
present with seiuzres, focal neuro deficits (gradual), headaches
diffuse tend to become anaplastic over time
What are the various grades/names for astrocytomas?
grade 1-pilocytic astrocytoma
grade 2- diffuse astrocytoma
grade 3-anaplastic astrocytoma
grade 4-glioblastoma multiforme
Describe diffuse astrocytoma histology
cellularity moderately increased and occasional nuclear atypia
Describe anaplastic astrocytoma histology
increased cellularity distinct nuclear atypia, marked mitotic activity
Describe glioblastoma multiforme histology
pleomorphic astrocytic cells, brisk mitotic activity, prominent microvascular proliferation
has necrosis with pseudopalisading
Describe pilocytic astrocytoma histology
biphasic pattern: densely fibrillary (pilocytic) areas alternating with microcystic component
rosenthal fibers
What are key clinical features of pilocytic astrocytoma?
cerebellum, also optic nerve, 3rd ventricle, hypothalamus, brainstem and occasionally cerebral hemispheres
1st 2 decades
presents with focal neurologic deficits, seizures, or S/S of increased intracranial pressure
What does pilocytic astrocytoma look like on imaging?
well demarcated, often cystic contrast-enhancing tumor
mural nodule
What is a significant mutation realted to oligodendromglioma?
loss of 1p and 19q are predictors of prolonged survival and susceptibility to chemotherapy in anaplastic oligodendrogliomas
What are some key clinical features of oligodendroglioma?
5th to 6th decade
long history of progressive neuro sx (seizures, headache, focal signs)
better survival than astrocytomas (5-10 yrs for grade II)
What does an oligodendroglioma look like on imaging?
well defined hypodense/hypointense mass, may see calcification
What does oligodendroglioma histology look like?
round nuclei, freid egg cell and calcifications
What are key features of ependymomas?
children and young adults
occurs along ventricular system, usually posterior fossa (4th ventricle)
hydrocephalus, occasonially seizures
avg survival 4 yrs
may invade brain parenchyma
may disseminate through subarachnoid space
What does ependymoma look like on imaging?
well circumscribed mass
What is seen on histology for ependymoma?
true rosettes-columnar cells arranged around central lumen
perivascular pseudorosettes
anaplastic ependymoma-increased mitoses & vascular proliferation
What are key features of choroid plexus papillomas?
1st 2 decades
4th ventricle, lateral ventricle, 3rd ventricle, cerebello-pontine angle
presents with hydrocephalus
can progress to choroid plexus carcinoma (usually in children)
good prog unless progresses to carcinoma
How can you distinguish a choroid plexus papilloma from a choroid plexus carcinoma/
papillomas do not invade adjacent parenchyma but carcinomas do
What are the key features of colloid cysts?
usually attached to roof of 3rd ventricle
intermittent obstruction of foramen of monro (positional)
positional headache, thin walled cyst lined by cuboid/columnar epithelium
What are the eky features of ganglioglioma?
first 3 decades
long standing history of seizures is common
usually supretentorial and in temporal lobe
surgery usually curative
What does a ganglioglioma look like on imaging?
solid or cycstic well circumcribed mass, mural nodule, calcification
What does histology of a ganglioglioma look like?
atypical ganglion cells (neurons) and neoplastic glial component
What are the key clinical features of medulloblastoma?
primitive neuroectodermal neoplasm of posterior fossa
first decade
cerebellar dysfunction
incrased intracranial pressure
solid, well defined homogenous mass, tendency to spread through subarachnoid space and for drop metastases
What does a medulloblastoma look like on imaging?
well defined, contrast enhancing mass, may see leptomeningeal spread
What does medulloblastoma look like on histology?
homer wright rosettes
synaptophysin immunoreactivity
highly cellular and composed of undifferentiated cells
What are the key features of primary CNS lymphomas?
40-60 yo typically immunocompirmised more common, EBV assoc non specific symptoms, referable to mass lesion usually Bcell poor prognosis usually supratentorial
What are key features of meningiomas?
most common extraparenchymal neoplasm of CNS
middle to late adult life
usually women
sx due to enlarging mass
How do meningiomas look on imaging?
dural based, vascular, contrast enhancing, well defined
What are 2 associations with meningiomas?
radiation tx
NF2
Describe the 3 grades of meningiomas
1(typical): excellent 5 yr survival
2 (atypical): high mitotic index or architectural loss, hypercellularity, macronucleoli, small cell differentiation or brain invasion
3 (anaplastic): excessive mitotic activity or loss of meningothelial differentiation
What does meningioma histology look like?
sheets of tumor cells with indistinct borders
whorls
round to oval nuclei, dispersed chromatin, wispy eosinophilic cytoplasm
psammomma bodies
necrosis, brain invasion
What are common clinical signs/sx of metastatic turmos to the CNS?
headaches
focal neurologic signs
altered mental status
How mets to the CNS usually look on imaging?
distinct, contrast enhancing mass with surrounding edema, usually multiple
Where to mets to the CNS usually come from?
lung or breast
sometimes kidney, GI, skin (malignant melanoma)
Hwat are key features of peripheral nerve sheath tumors (schwannomas)?
benign tumor composed of schwann cells 4th to 6th decades peripheral nerves, usaully in head and neck (ie vestibulocochlear) spinal tumors-radicular pain hearing loss, facial numbness well definted contrast enhancing mass associated w/NF2
What does schwannoma histology look like?
antoni A: compact spindle cells
antoni B: loose spongy areas, small cells with round nuclei
What is a neurofibroma?
benign tumor of schwann cells, fibroblasts and perineural cells
associated with NF1
cutaneous neorfibroma or peripheral nerve forms
What does neurofibroma histology look like?
hypocellular, elongated spindle cells with wavy nuclei
diffusely infiltrate adjacent nerve and soft tissue
What are key features of plexiform neurofibroma?
almost exclusively in NF1
transformation of mutiple fascicles of nerves into neurofibroma with preservation of anatomic configuration
typically affects larger nerves or a plexus
high likelihood of malignant transformation
What are key features of malignant peripheral nerve sheath tumors?
usually in extremities in CNS assoc w/CN V strong assoc w NF1 high grade, agressive infiltrative non-encapsulated fleshy masses
What does malignant peripheral nerve sheath tumor histology look like?
highly cellular, moderate to marked nuclear pleomorphism
high mitotic rate
What are key features of neurofibromatosis type 1? (von Recklinghausen disease)
AD
1/3000
neurfibromas, cafe au lai spots, lisch nodules (pigmented hamartomas in iris), optic glioma, osseous lesions, axillary freckling, family hx
Where is the neurofibromatosis 1 gene found?
chromosome 17
gene product: neurofibromin
What are key features of NF2?
AD 1/40,000-50,000 gene on chromosome 22 gene product is merlin bilateral vestibular schwannomas, fam hx, meningiomas, schwannomas, gliomas, neurofibromas, lens opacity, cerebral calcifications
What chromosome is the VHL gene found on?
3
What are key features of von hippl lindau disease?
hemangioblastomas of CNS and retina
renal cell carcinoma
pheochromocytoma
visceral cysts
What do hemangioblastomas look like on imaging?
well-defined, contrast enhancing cystic mass with mural nodule
What do hemangioblastomas look like on histology?
numerous vessels interspersed wit hstromas cells
stromal cells have abundant foamy cytoplasm (contains fat)
What are key features fo tuberous sclerosis?
AD
casued by mutations in TSC1 (chr 9)-hamartin &
TSC2 (chr 16)-tuberin
cortical hamartomas
subcortical glioneuronal hamrtomas
subependymal giant cell astrocytomas
cutaneous angiofibromas, subungual fibromas, cardiac rhabdomyomas, intestinal polyps, etc
What do tubers look like on histology?
neuronas haphazardly arranged in cortex
often have glial as well as neuronal features
What are key features of subependymal giant cell astrocytoma?
cause obstructive hydrocephalus
exophytic solid well-defined mass arising in the wall of lateral ventricle
large pleomrophic multinucleated tumor cells w/eosinophilic cytoplasm
may be of astrocytic or glioneuronal origin
no malignant transformation, local invasion reported
What malignancies most commonly cause paraneoplastic syndromes?
small cell carcinoma gynecologic malignancies hodgkin's and non-hodgkins lymphoma testicular cancer neuroblastoma
What are the 2 main categories or paraneoplastic syndromes?
- related to ectopic hormone production
2. neurologic syndromes (rare)
Describe subacute cerebellar ataxia
a paraneoplastic neurologic syndrome
progressive ataxia, dysarthria, nystagmus, vertigo, diplopia, titubation
associated w/ ovarian and breast cancer
ab to purkinje cells
Describe Lambert Eaton Myasthenic syndrome
a paraneoplastic neurologic syndrome
muscle weakness, esp in the legs that improves with testing on exam (extraocular muscle are spared)
Ab to P/Q type voltage gated calcium channels, leads to decreased ACh release
most commonly assoc w/SCLC
