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
|
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
|
|
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. |
|
|
