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CNS tumors
CBN III
44
Medical
Graduate
02/04/2011

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Term
what characterizes the incidence of brain tumors?
Definition
~50% are primary, the rest are metastatic. primary brain tumors account for 20% of cancers in children under 15 y/o.
Term
what is the range of clinical presentation for CNS tumors?
Definition
focal/generalized seizures, focal neurologic sings and signs of ICP (severe unremitting h/a, n/v). death is usually associated w/complications from increased ICP.
Term
what is the prognosis related to w/CNS tumors?
Definition
benign/malignant behavior, invasion/destruction of vital centers, and surgical accessibility.
Term
how common are extracranial CNS metastases?
Definition
rare: the brain has no lymphatics - though tumors can spread along the subarachnoid space.
Term
what CNS tumors are more common in males? females?
Definition
males: glioma. females: meningiomas.
Term
what CNS tumors can radiation exposure contribute to?
Definition
meningiomas, gliomas, and nerve sheath tumors
Term
what are primary CNS lymphomas linked to?
Definition
immunodeficiency. ex. HIV: often leads to non-hodgkin's lymphoma and B cell lymphoma
Term
what are the glial cells which can become gliomas?
Definition
astrocytes (grades I-IV), ependymal cells (ependymoma), oligodendrocytes (oligodendroglioma)
Term
what characterizes astrocytomas grade I?
Definition
aka *pilocytic astrocytoma* these are the least severe, do not infiltrate, rarely progress to a higher grade and a better prognosis. they have a different genetic profile.
Term
what is the morphology of astrocytomas grade I/pilocytic astrocytomas?
Definition
these are well circumscribed mural nodules, associated w/a cyst and some compact and microcystic areas (relatively loose parenchyma). the cells have piloid hairlike processes (pilocytic), thickened rosenthal fibers, and thickened blood vessels may be present.
Term
what characterizes astrocytoma grades II-IV?
Definition
these have a diffusely infiltrative growth pattern (difficult to remove). astrocytoma II is characterized by pleomorphism (more cellular) and anaplastic astrocytoma grade III is characterized by (mitoses+cellularity = high growth rate and infiltration). astrocytoma grade IV/glioblastoma multiforme is characterized by *marked vascular proliferation w/production of VEGF*, hemorrhage, necrosis (slow/poor vascularization), and a *pseudo-palisading pattern of cells in the tumor. grades II/III usually progress to grade IV (glioblastoma multiforme) which diffusely expands to white matter, is poorly demarcated, and most have a dense meshwork of cytoplasmic processes. this is a common primary tumor of the brain (cerebral cortex - seizures) in adults, rapidly progressing and can kill due to mass effect w/in 1 year.
Term
how does glioblastoma multiforme appear grossly?
Definition
necrosis, hemorrhage, not well demarcated, and possible butterfly wing pattern. this is a necrotic, hemorrhagic, edematous and anaplastic fast-growing lesion.
Term
what characterizes the pseudopalisading nature of glioblastoma multiforme?
Definition
a dense infiltration of neoplastic cells start to form a wall composed of cells which are in a wide variety of sizes/shapes: polygonal, cylindrical, oblong, dense and crowded.
Term
what characterizes oligodendrogliomas?
Definition
these make up 5-15% of primary CNS tumors. there is no gender preference, they present in adulthood, are associated w/epilepsy, are more chemosensitive, associated w/hemorrhage, **calcifications, and **chromosome 1p, 19q deletions.
Term
what is the morphology of oligodendrogliomas?
Definition
oligodendrogliomas diffusely infiltrate the cortex and are composed of uniform cells *w/perinuclear halos (fried egg nuclei), round nuclei and branching capillaries.
Term
what characterizes ependymomas?
Definition
these comprise 5-10% of all primary CNS neoplasms, are the third most common brain tumor in *children, **most are infratentorial circumscribed tumors** and grow near the ependyma lined ventricles or spinal cord central canal. the intraspinal tumors may be completely excised. CSF dissemination is common and cytology can play a role in dx.
Term
what is the morphology of ependymomas?
Definition
ependymomas may have solid or papillary growth and be associated w/ependymal canals, rosettes (tumor cells surrounding blood vessels/necrosis/amyloid), and perivascular pseudorosettes (doesn't totally surround).
Term
what clinical symptoms are associated w/ependymomas?
Definition
gait abnormalities, ataxia from location near cerebellum, and increased intracranial pressure symptoms such as nausea, vomiting and headaches
Term
what is a myxopapillary ependymoma?
Definition
a specific type of ependymoma found in the **filum terminale of the spinal cord and composed of *cuboidal cells around papillary cores in a myxoid background*. these are biologically benign, but prognosis depends on the extend of excision.
Term
what is a subependymoma?
Definition
this grade I tumors arises in the 4th or lateral ventricles and is slow growing (may form a small lesion). subependymomas may be incidental on autopsy, calcified, highly fibrillar and low in cellularity.
Term
what characterizes medulloblastomas?
Definition
these are *highly malignant, poorly differentiated and make up 20% of *childhood brain tumors. in children medulloblastomas are found in the midline cerebellum, but laterally in adults. they may be associated w/hydrocephalus, CSF spread is common, they are radiosensitive and *similar tumors in other locations are called primitive neuroectodermal tumors* (PNET)
Term
what characterizes medulloblastomas histologically?
Definition
medulloblastomas are highly cellular w/increased mitoses, high n/c ratio, *karyorrhexis (large clumping of chromatin in the nuclei) is common, as are *homer-wright rosettes and flexner-wintersteiner rosettes (tumor cells surround a blood vessel or other type of material).
Term
what characterizes meningiomas?
Definition
meningiomas are the most common extra axial tumor, the most common non-glial brain tumor in adults and more common in middle-age females. meningiomas arise from arachnoid cap cells, are slow growing dural based masses and may be associated w/hyperostosis of overlying skull.
Term
can radiation increase risk of meningoma formation?
Definition
yes
Term
what kind of receptors may meningiomas express?
Definition
progesterone receptors - which may provide tx if not surgically accessible (infratentorial, brain stem). females during their menstrual cycle may experience an exacerbation of symptoms.
Term
what genetic associations exist for meningiomas?
Definition
*neurofibromatosis type 2 and deletion of chr 22q*
Term
what characterizes meningiomas morphologically?
Definition
meningiomas are benign, rounded, well circumscribed masses which can compress the brain = seizures/headache. *psammoma bodies (concentric laminations) are associated and grossly: *gritty, golf-ball-like growth which grows from the dura and "dents" the brain. the *en plaque variant is a carpet-like growth and can induce hyperostosis (less nodular).
Term
what are the meningoma grades?
Definition
I-III, the higher the grade, the more brain invasion w/frank malignant changes (not all are benign). surgical accessibility is important.
Term
what characterizes hemangioblastomas?
Definition
this CNS manifestation of von hippel-lindau disease is autosomal dominant (chr 3p) and can develop tumors in the cerebellum, retina, brainstem, spinal cord, pancreas, liver, and renal cells.
Term
how do hemangioblastomas appear grossly? microscopically?
Definition
grossly: cerebellar cyst w/a mural nodule. microscopically: a mixture of delicate capillary vessels, loose stroma cells *w/multiloculated (holes) cytoplasm, large tortuous blood vessels w/large lumens, and the potential for bleeding (expands and produces edema).
Term
what characterizes choroid plexus neoplasms?
Definition
these *papillary neoplasms mostly present during the first decade of life (CA before 3 yrs), and are found in the lateral/3rd ventricle in children while in the 4th ventricle in adults. they appear as solid areas w/necrosis and mitoses.
Term
what characterizes schwannomas?
Definition
these benign encapsulated tumors arise from schwann cells, are seen in 30-60 y/os, are associated w/sensory nerves - intracranially: acoustic neuroma of CN8/CN5 and spinally: posterior sensory nerves.
Term
what characterizes schwannomas histologically?
Definition
these spindle cell tumors (cigar-shaped nuclei) have alternating dense (antoni A) and loose (antoni B) regions, *verocay bodies (alignment/palisading of nuclei), and *hyalinized blood vessels (thickened hazy wall).
Term
what characterizes neurofibromatosis type 1?
Definition
multiple neurofibromas and pilocytic astrocytomas due to mutations of *chr 17
Term
what characterizes neurofibromatosis type 2?
Definition
bilateral acoustic schwannomas, multiple ependymomas and meningiomas due to mutations on *chr 22. MIMSE: multiple inherited schwannomas, meningiomas and ependymomas. this involves neoplastic proliferation of schwann cells, fibroblasts and perineurial-like cells causing expansion of the nerve = risk of malignant transformation.
Term
what characterizes neurofibromatosis grossly?
Definition
subcutaneous lesions composed of fibrous and nerve tissue - can be painful and range in size from a few mm to several cm. this can eventually disfigure the entire musculoskeletal system.
Term
what characterizes germ cell tumors in the CNS?
Definition
germ cell tumors can arise from primordial tissue derived from ectoderm, mesoderm, or endoderm - usually along the midline. the pineal gland is the most common site (esp in males) and the suprasellar region is the 2nd most common site. features resemble the seminoma in the testis and dysgerminoma in the ovary. these germ cells are large w/distinct borders, large vesicular nuclei and prominent nucleoli. mitoses and necrosis is common and infiltration of lymphocytes (mostly T cells) is also seen.
Term
what characterizes primary CNS lymphomas?
Definition
most primary CNS lymphomas will arise in the setting of immunodeficiency, often HIV/AIDS. usually primary CNS lymphomas are non-hodgkins, of B cell origin and radiosensitive - but w/poor prognosis. they are often angiocentric and appear soft gray pink w/areas of necrosis and hemorrhage.
Term
what characterizes metastatic tumors?
Definition
these usually spread via hematogenous route (brain lacks lymphatics - but the spinal cord does involve them). leukemias and lymphomas thus may infiltrate the CSF. most metastatic tumors regardless of origin tend to be multiple in their presentation.
Term
how to pts w/tumors metastatic to the CNS present clinically?
Definition
h/a and focal neurological s/s are common - also papilledema and seizures. in a pt over 60 y/o w/new onset seizures - strongly consider metastasis. with the vast majority of metastatic carcinomas/sarcomas to the brain there isn’t much you can do once it gets there.
Term
what is the morphology of CA metastasis to the CNS?
Definition
usually: localized to the gray-white junction, more common in the *cerebral cortex than the cerebellum, often in the distribution of the *MCA and brainstem mets are rare.
Term
what kinds of metastatic CA to the CNS usually give hemorrhagic mets?
Definition
*melanoma, choriocarcinoma, lung CA (adenocarcinoma and small cell), and renal cell CA.
Term
what characterizes the histology of CNS metastasis?
Definition
histology is similar to the primary tumor. vascular proliferation is uncommon, necrosis is seen w/islands of tumor cells, **most have well-defined borders, and small cell CA/melanoma have more of an infiltrative pattern.
Term
what is the prognosis for CNS metastasis?
Definition
poor. if untreated, survival is generally weeks. radiation/sx may increase survival to 3-6 mos.
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