What is the Fibroblastic pattern?
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The Fibroblastic pattern refers to a histological appearance characterized by the proliferation of fibroblast-like cells, often seen in certain types of tumors, indicating a reactive or neoplastic process.
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What is the Fibroblastic pattern?
The Fibroblastic pattern refers to a histological appearance characterized by the proliferation of fibroblast-like cells, often seen in certain types of tumors, indicating a reactive or neoplastic process.
What is a Low grade Astrocytoma?
A Low grade Astrocytoma is a type of brain tumor that arises from astrocytes and is characterized by slow growth and a lower degree of malignancy compared to high-grade tumors.
What are primary tumors in the context of CNS tumors?
Primary tumors account for half to three quarters of all CNS tumors and 20% of all pediatric tumors.
What is the significance of multicentricity in metastatic melanoma?
Multicentricity refers to the presence of multiple tumor sites within the same organ or tissue, indicating a more aggressive disease course in metastatic melanoma.
What is Central neurocytoma?
Central neurocytoma is a rare, typically benign brain tumor that arises from neuronal precursors, often found in the lateral ventricles of the brain.
What is Medulloblastoma?
Medulloblastoma is a type of aggressive brain tumor that primarily affects children, originating in the cerebellum and often spreading to other parts of the central nervous system.
What are Germ Cell Tumors?
Tumors of the young, with 90% occurring during the first 2 decades, primarily located along the midline, most commonly in the pineal and suprasellar regions.
What are pilocytic astrocytomas?
Relatively benign tumors that are more common in children and young adults, typically located in the cerebellum, third ventricle, optic pathways, spinal cord, and occasionally in the cerebral hemispheres.
What is an Ependymoma?
Ependymoma is a type of tumor that arises from ependymal cells, which line the ventricles of the brain and the central canal of the spinal cord. It can occur in both children and adults and is classified as a primary central nervous system tumor.
What is Psammomatous?
Psammomatous refers to a type of tumor characterized by the presence of psammoma bodies, which are calcified structures often found in certain types of tumors, particularly meningiomas.
What are Pilocytic astrocytomas?
Pilocytic astrocytomas are a type of brain tumor characterized by bipolar cells with long, thin 'hairlike' processes that are GFAP-positive, along with the presence of Rosenthal fibers, eosinophilic granular bodies, and microcysts. Necrosis and mitoses are rare in these tumors.
What defines a Glioblastoma?
Glioblastoma has a histologic appearance similar to that of anaplastic astrocytoma, but it also features necrosis (often with pseudopalisading nuclei) or vascular proliferation.
What is an Ependymoma?
A type of tumor that arises next to the ependymal-lined ventricular system, including the central canal of the spinal cord, commonly found near the fourth ventricle in the first two decades of life and in the spinal cord in adults.
What is an Astrocytoma?
Astrocytoma is a type of tumor that arises from astrocytes, the star-shaped glial cells in the brain and spinal cord.
What does expanded white matter of the left cerebral hemisphere indicate in relation to low-grade astrocytoma?
Expanded white matter of the left cerebral hemisphere may indicate the presence of a low-grade astrocytoma, as these tumors can cause localized swelling and changes in the brain's structure.
What are Gliomas?
Gliomas are tumors classified histologically based on their resemblance to different types of glial cells, including astrocytomas, oligodendrogliomas, and ependymomas.
What are Psammomatous bodies in Meningiomas?
Numerous psammoma bodies.
What virus is nearly always positive in Metastatic/Primary Central Nervous System Lymphoma?
The oncogenic Epstein-Barr virus.
How does the prognosis of Oligodendrogliomas compare to that of astrocytomas?
Oligodendrogliomas have a better prognosis than patients with astrocytomas of similar grade.
What is an Anaplastic oligodendroglioma?
Anaplastic oligodendroglioma is a more aggressive subtype of oligodendroglioma classified as WHO grade III/IV, characterized by higher cell density, nuclear anaplasia, and increased mitotic activity.
What is Primary CNS Lymphoma?
Primary CNS Lymphoma is a type of cancer that originates in the central nervous system, specifically in the brain or spinal cord, and is characterized by the presence of lymphoma cells.
What is Glioblastoma?
A densely cellular tumor characterized by necrosis and pseudopalisading of tumor cell nuclei.
What is the Syncytial pattern?
The Syncytial pattern refers to a histological arrangement where cells fuse together to form a multinucleated structure, often seen in certain types of tumors.
What is a low-grade astrocytoma?
A low-grade astrocytoma is a type of brain tumor characterized by slow growth and a lower degree of malignancy, often found in the white matter of the brain.
What is Central neurocytoma?
A low-grade neoplasm located within and adjacent to the ventricular system, typically found in the lateral or third ventricles, characterized by evenly spaced, round, uniform nuclei and often islands of neuropil.
What is an Oligodendroglioma?
Oligodendroglioma is an infiltrative tumor characterized by gelatinous, gray masses that may show cysts, focal hemorrhage, and calcification.
What is an Astrocytoma?
Astrocytoma is a type of brain tumor that arises from astrocytes, which are star-shaped glial cells in the brain. It is categorized into three groups based on histologic features: well-differentiated astrocytoma (grade II), anaplastic astrocytoma (grade III), and glioblastoma (grade IV).
What age group is most commonly affected by Diffuse astrocytomas?
Diffuse astrocytomas typically affect individuals in their fourth through sixth decades of life.
In which population is Metastatic/Primary Central Nervous System Lymphoma most common?
It is the most common CNS neoplasm in immunosuppressed persons.
What is the significance of early diagnosis in Germ Cell Tumors?
Early diagnosis of Germ Cell Tumors is crucial as it can lead to more effective treatment options and better prognosis for the patient.
What is Oligodendroglioma?
Oligodendroglioma is a type of brain tumor characterized by sheets of regular cells with spherical nuclei containing finely granular chromatin, surrounded by a clear halo of cytoplasm, and often associated with calcification in 90% of cases. Mitotic activity is usually difficult to detect.
What is brain metastasis?
Brain metastasis refers to the spread of cancer cells from a primary tumor located in another part of the body to the brain.
How do childhood CNS tumors differ from adult CNS tumors?
Childhood CNS tumors differ from adults in both histologic subtype and location, typically arising in the posterior fossa, whereas adult tumors are mostly supratentorial.
What is a meningioma with a whorled pattern of cell growth and psammoma bodies?
A meningioma characterized by a distinctive whorled pattern of cellular arrangement and the presence of psammoma bodies, which are calcified structures often found in certain tumors.
What is a Central neurocytoma?
A Central neurocytoma is a type of neuronal tumor that typically arises in the lateral ventricles of the brain and is characterized by a well-circumscribed mass of neurocytic cells.
What characterizes Atypical meningiomas?
Atypical meningiomas (WHO grade II) are characterized by prominent nucleoli, increased cellularity, pattern-less growth, and a higher mitotic rate.
What is the NF2 tumor suppressor gene?
A gene located on the long arm of chromosome 22 (22q) that, when mutated, is associated with about half of meningiomas not linked to NF2.
What is the male predominance in Germ Cell Tumors?
There is a male predominance in the pineal region for Germ Cell Tumors.
What percentage of adult gliomas are Diffuse astrocytomas?
Diffuse astrocytomas account for 80% of adult gliomas.
What factors influence the prognosis of meningiomas?
The prognosis of meningiomas depends on lesion size and location, surgical accessibility, and histologic grade.
What defines the Secretory pattern in Meningiomas?
Gland-like PAS-positive eosinophilic secretions (pseudopsammoma bodies).
What percentage of extranodal lymphomas does Metastatic/Primary Central Nervous System Lymphoma represent?
It represents 2% of extranodal lymphomas.
Where can Germ Cell Tumors occur in the CNS?
Germ Cell Tumors can occur in the central nervous system, particularly in the pineal gland and the suprasellar region.
What are the characteristics of Oligodendroglioma?
Oligodendroglioma tumor cells have round nuclei with a cytoplasmic halo and thin blood vessels in the background that form an interlacing pattern.
What are Anaplastic Astrocytomas?
Anaplastic astrocytomas are a type of malignant brain tumor that arises from astrocytes, characterized by increased cellularity, nuclear atypia, and a higher mitotic rate compared to lower-grade astrocytomas.
What is Glioblastoma?
A necrotic, hemorrhagic, infiltrating mass that is a highly aggressive type of brain tumor.
What is a parasagittal multilobular meningioma?
A parasagittal multilobular meningioma is a type of tumor that is attached to the dura mater and causes compression of the underlying brain tissue.
What is Medulloblastoma?
Medulloblastoma is a type of aggressive brain tumor that primarily occurs in the cerebellum, commonly affecting children and characterized by rapid growth and potential to spread to other parts of the central nervous system.
What is the characteristic microscopic feature of Central Nervous System Lymphoma Tumors?
Malignant cells accumulate around blood vessels and infiltrate the surrounding brain parenchyma.
What defines Anaplastic (malignant) meningiomas?
Anaplastic meningiomas (WHO grade III) are highly aggressive tumors that resemble high-grade sarcomas or carcinomas.
What is the typical age group for meningiomas?
Meningiomas mostly occur in adults.
What are Anaplastic ependymomas?
Anaplastic ependymomas are a type of ependymoma characterized by increased cell density, high mitotic rates, necrosis, and less evident ependymal differentiation.
What is the Transitional pattern?
The Transitional pattern is a histological classification observed in certain CNS tumors, characterized by a mixture of features from different tumor types, often seen in meningiomas.
What is the definition of Secretory?
Relating to the process of secretion, which is the release of substances from cells or glands.
What are Gangliogliomas?
Gangliogliomas are rare, slow-growing tumors that typically contain both neuronal and glial components, often found in the temporal lobe of the brain.
What is Medulloblastoma?
Medulloblastoma is a highly cellular brain tumor characterized by sheets of anaplastic ('small blue') cells, which have little cytoplasm and hyperchromatic nuclei, along with abundant mitoses and often focal neuronal differentiation such as Homer Wright or neuroblastic rosettes.
What is the most common type of Embryonal Neoplasm?
The most common type of embryonal neoplasm is medulloblastoma, which accounts for 20% of pediatric brain tumors.
Where do Germ Cell Tumors most commonly occur?
Most commonly in the pineal and suprasellar regions along the midline.
What age group is most affected by pilocytic astrocytomas?
Children and young adults.
How do meningiomas typically interact with the underlying brain?
Most meningiomas are easily separable from the underlying brain, although some infiltrate the brain, which is associated with an increased risk of recurrence.
What are Ependymomas?
Ependymomas are a type of glioma that resemble ependymal cells, which line the ventricles of the brain and the central canal of the spinal cord.
What are Germ Cell Tumors?
Germ Cell Tumors are a type of tumor that originates from germ cells, which are the cells that develop into sperm and eggs. They can occur in various locations, including the gonads and the central nervous system.
How do Metastatic Tumors typically present in the brain?
Metastatic tumors typically present as sharply demarcated masses, often located at the gray-white junction, and can elicit edema.
What are the treatment options for Germ Cell Tumors?
Treatment options for Germ Cell Tumors typically include surgery, chemotherapy, and radiation therapy, depending on the tumor type and location.
Where are Oligodendrogliomas commonly located?
Oligodendrogliomas are mainly located in the cerebral hemispheres, particularly in the frontal or temporal lobes.
What are the unique characteristics of tumors of the nervous system?
Tumors of the nervous system do not have detectable premalignant or in situ stages, even low-grade lesions may infiltrate large regions of the brain, the anatomic site of the neoplasm can influence outcome, they are independent of histologic classification due to local effects, and they rarely spread outside of the CNS.
What is an Astrocytoma?
Astrocytoma is a type of poorly defined, gray, infiltrative tumor that can vary in consistency from firm to soft and gelatinous, often exhibiting cystic degeneration and variations in gross appearance, particularly in glioblastoma, which may appear yellow due to tissue necrosis.
What is an Embryonal Neoplasm?
Embryonal neoplasms are tumors of neuroectodermal origin that exhibit a primitive 'small round cell' appearance, similar to normal progenitor cells in the developing CNS, with limited differentiation that may progress along multiple lineages.
What are Rosenthal fibers?
Rosenthal fibers are elongated, eosinophilic structures found in pilocytic astrocytomas, indicative of the tumor's astrocytic origin.
What are primitive neuroectodermal tumors (PNETs)?
Tumors of similar histologic type and poor differentiation that can be found elsewhere in the nervous system, related to Medulloblastoma.
What are meningiomas?
Meningiomas are tumors that arise from arachnoid meningothelial cells, primarily occurring in adults.
What types of growth patterns are associated with mutations in NF2?
Mutations in NF2 are more common in tumors with fibroblastic, transitional, and psammomatous growth patterns.
What are Astrocytomas?
Astrocytomas are a type of glioma that resemble astrocytes, which are star-shaped glial cells in the brain.
What is Metastatic/Primary Central Nervous System Lymphoma?
An aggressive disease characterized by multiple tumor nodules within the brain parenchyma, often associated with immunosuppressed individuals and linked to the Epstein-Barr virus.
Where is the typical location of a Dysembryoplastic neuroepithelial tumor?
The superficial temporal lobe.
What is Astrocytoma?
Astrocytoma is a type of brain tumor characterized by a mild to moderate increase in the number of glial cell nuclei, variable nuclear pleomorphism, a fibrillary appearance in the background, and an indistinct transition between neoplastic and normal tissue.
What are Primary CNS tumors classified as?
Primary CNS tumors are classified as Gliomas, Neuronal Tumors, Embryonal (Primitive) Neoplasms, Germ Cell Tumors, Meningiomas, and Lymphoma.
What is an Anaplastic astrocytoma?
Anaplastic astrocytomas are characterized by regions that are more densely cellular, greater nuclear pleomorphism, and the presence of mitotic figures.
What is Ependymoma?
Ependymoma is a type of tumor that can present as solid or papillary masses extending from the ventricular floor, commonly found in the fourth ventricle.
What are Metastatic/Primary Central Nervous System Lymphoma Tumors?
Aggressive large B-cell lymphomas that often occur in deep gray structures, white matter, and the cortex, with common periventricular spread and extensive areas of necrosis associated with EBV.
What are Meningiomas associated with NF2?
Multiple meningiomas that occur in association with eighth-nerve schwannomas or glial tumors.
What is a perivascular pseudorosette in Ependymoma?
A perivascular pseudorosette is a histological feature of Ependymoma where tumor cells are arranged around blood vessels, with an intervening zone containing thin ependymal processes.
Where are Diffuse astrocytomas commonly located?
Diffuse astrocytomas are commonly located in the cerebral hemispheres.
What are Metastatic Tumors?
Metastatic tumors are secondary tumors that originate from primary cancers, mostly carcinomas, and account for one fourth to one half of intracranial tumors.
What are Pilocytic astrocytomas?
Pilocytic astrocytomas are typically cystic tumors characterized by a mural nodule in the wall of the cyst, and if solid, they are usually well circumscribed.
What are Gangliogliomas?
Gangliogliomas are tumors that manifest with seizures and are characterized by a mixture of glial elements, usually a low-grade astrocytoma, and mature appearing neurons. The glial component can occasionally become frankly anaplastic, but most of these tumors are slow-growing.
What are Pilocytic astrocytomas?
Pilocytic astrocytomas are a type of brain tumor characterized by the presence of hair-like cells and Rosenthal fibers.
What are hair-like cells?
Hair-like cells are a distinctive feature of pilocytic astrocytomas, contributing to their unique histological appearance.
What genetic mutations are associated with Glioblastoma?
Glioblastoma is associated with loss-of-function mutations in the p53 pathway, mutations in the Rb tumor suppressor pathways, and gain-of-function mutations in the oncogenic PI3K pathways.
What is the Syncytial pattern in Meningiomas?
Whorled clusters of cells without visible cell membranes that sit in tight groups.
What characterizes the Fibroblastic pattern in Meningiomas?
Elongated cells and abundant collagen deposition between.
What are Oligodendrogliomas?
Oligodendrogliomas are a type of glioma that resemble oligodendrocytes, which are glial cells that produce myelin in the central nervous system.
What are the microscopic features of a Dysembryoplastic neuroepithelial tumor?
Small round neuronal cells arranged in columns, forming multiple discrete intracortical nodules with a myxoid background and well-differentiated floating neurons within pools of mucopolysaccharide-rich myxoid fluid.
What are the most common primary sites for Metastatic Tumors?
The most common primary sites for metastatic tumors are the lung, breast, skin (melanoma), kidney, and gastrointestinal tract, accounting for about 80% of cases.
What is an Oligodendroglioma?
A type of glioma that accounts for 5% to 15% of gliomas, typically found in the cerebral hemispheres, mainly in the frontal or temporal lobes, and has a better prognosis than astrocytomas of similar grade.
What genetic mutations are associated with Oligodendrogliomas?
Oligodendrogliomas are associated with deletions of chromosomes 1p and 19q, which make them highly responsive to chemotherapy and radiotherapy.
What is a Dysembryoplastic neuroepithelial tumor?
A Dysembryoplastic neuroepithelial tumor is a rare, benign brain tumor typically found in children and young adults, characterized by a mixture of glial and neuronal elements, often associated with epilepsy.
What are Meningiomas?
Meningiomas are well-defined dura-based masses that do not invade the brain, although they may extend into the overlying bone.
What is Medulloblastoma?
A type of brain tumor located in the midline of the cerebellum, commonly found in children, with lateral tumors occurring in adults. It is characterized by a well-circumscribed, gray, and friable appearance.
What are Gangliogliomas?
Gangliogliomas are mixed neuronal-glial tumors that often occur in the temporal lobe and are composed of both ganglion cells and glial cells.
How do Central Nervous System Lymphoma Tumors compare to glial neoplasms and metastases?
They are relatively well defined compared to glial neoplasms but not as discrete as metastases.
What features are shared in the Transitional pattern of Meningiomas?
Shares features of the syncytial and fibroblastic types.
What are common presentations of Diffuse astrocytomas?
Common presentations of Diffuse astrocytomas include seizures, headaches, and focal neurologic deficits.
What do well-demarcated margins indicate in metastatic melanoma?
Well-demarcated margins suggest a clear boundary between the tumor and surrounding tissue, which can be associated with a better prognosis in metastatic melanoma.
What is Medulloblastoma?
A type of brain tumor that predominantly occurs in children and is exclusively located in the cerebellum, characterized by the expression of neuronal and glial markers.
What is Ependymoma?
Ependymoma is a type of tumor that arises from ependymal cells, characterized by cells with regular, round to oval nuclei, abundant granular chromatin, and a fibrillary background. It may show rosettes and canals resembling the embryologic ependymal canal.
What are the microscopic features of Ependymoma?
Microscopically, Ependymoma features cells with regular, round to oval nuclei, abundant granular chromatin, a fibrillary background, and may exhibit rosettes and perivascular pseudorosettes, where tumor cells are arranged around vessels with thin ependymal processes in between.
What is a Dysembryoplastic neuroepithelial tumor?
A Dysembryoplastic neuroepithelial tumor is a benign, slow-growing tumor commonly found in children and young adults, characterized by a unique histological appearance and often associated with epilepsy.
Where are pilocytic astrocytomas commonly located?
In the cerebellum, third ventricle, optic pathways, spinal cord, and occasionally in the cerebral hemispheres.
What genetic mutation is associated with pilocytic astrocytomas?
Activating mutations in the serine-threonine kinase BRAF.
What is a Dysembryoplastic neuroepithelial tumor?
A low-grade childhood tumor that grows slowly and has a good prognosis after resection, often manifesting as a seizure disorder.
What are the three histologic groups of astrocytomas?
The three histologic groups of astrocytomas are well-differentiated astrocytoma (grade II), anaplastic astrocytoma (grade III), and glioblastoma (grade IV).
What are the common types of Germ Cell Tumors?
The common types of Germ Cell Tumors include teratomas, seminomas, and non-seminomatous germ cell tumors, each with distinct characteristics and treatment approaches.
What age group is most affected by Oligodendroglioma?
Oligodendrogliomas primarily affect individuals in their fourth and fifth decades of life.
What mutations are found in lower-grade astrocytomas?
Lower-grade astrocytomas are characterized by mutations of IDH1 and IDH2.
What is the most common primary CNS germ cell tumor?
The most common primary CNS germ cell tumor is germinoma.
What percentage of brain tumors do Germ Cell Tumors represent?
Germ Cell Tumors represent 0.2% to 1% of brain tumors.
What is the response rate of Metastatic/Primary Central Nervous System Lymphoma?
It has a relatively poor response rate to treatment.
What is the age spectrum for nonimmunosuppressed individuals with Metastatic/Primary Central Nervous System Lymphoma?
The age spectrum is relatively wide, with more cases occurring after age 60.
What percentage of intracranial tumors is Metastatic/Primary Central Nervous System Lymphoma?
It accounts for 1% of intracranial tumors.
What is the microscopic characteristic of the boundary between Metastatic Tumors and brain parenchyma?
At the microscopic level, the boundary between metastatic tumors and brain parenchyma is sharp, often accompanied by surrounding reactive gliosis.