CNS Pathology

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.

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.

Primary tumors account for half to three quarters of all CNS tumors and 20% of all pediatric tumors.

Multicentricity refers to the presence of multiple tumor sites within the same organ or tissue, indicating a more aggressive disease course in metastatic melanoma.

Central neurocytoma is a rare, typically benign brain tumor that arises from neuronal precursors, often found in the lateral ventricles of the brain.

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.

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.

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.

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.

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.

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.

Glioblastoma has a histologic appearance similar to that of anaplastic astrocytoma, but it also features necrosis (often with pseudopalisading nuclei) or vascular proliferation.

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.

Astrocytoma is a type of tumor that arises from astrocytes, the star-shaped glial cells in the brain and spinal cord.

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.

Gliomas are tumors classified histologically based on their resemblance to different types of glial cells, including astrocytomas, oligodendrogliomas, and ependymomas.

Numerous psammoma bodies.

The oncogenic Epstein-Barr virus.

Oligodendrogliomas have a better prognosis than patients with astrocytomas of similar grade.

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.

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.

A densely cellular tumor characterized by necrosis and pseudopalisading of tumor cell nuclei.

The Syncytial pattern refers to a histological arrangement where cells fuse together to form a multinucleated structure, often seen in certain types of tumors.

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.

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.

Oligodendroglioma is an infiltrative tumor characterized by gelatinous, gray masses that may show cysts, focal hemorrhage, and calcification.

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).

Diffuse astrocytomas typically affect individuals in their fourth through sixth decades of life.

It is the most common CNS neoplasm in immunosuppressed persons.

Early diagnosis of Germ Cell Tumors is crucial as it can lead to more effective treatment options and better prognosis for the patient.

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.

Brain metastasis refers to the spread of cancer cells from a primary tumor located in another part of the body to the brain.

Childhood CNS tumors differ from adults in both histologic subtype and location, typically arising in the posterior fossa, whereas adult tumors are mostly supratentorial.

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.

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.

Atypical meningiomas (WHO grade II) are characterized by prominent nucleoli, increased cellularity, pattern-less growth, and a higher mitotic rate.

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.

There is a male predominance in the pineal region for Germ Cell Tumors.

Diffuse astrocytomas account for 80% of adult gliomas.

The prognosis of meningiomas depends on lesion size and location, surgical accessibility, and histologic grade.

Gland-like PAS-positive eosinophilic secretions (pseudopsammoma bodies).

It represents 2% of extranodal lymphomas.

Germ Cell Tumors can occur in the central nervous system, particularly in the pineal gland and the suprasellar region.

Oligodendroglioma tumor cells have round nuclei with a cytoplasmic halo and thin blood vessels in the background that form an interlacing pattern.

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.

A necrotic, hemorrhagic, infiltrating mass that is a highly aggressive type of brain tumor.

A parasagittal multilobular meningioma is a type of tumor that is attached to the dura mater and causes compression of the underlying brain tissue.

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.

Malignant cells accumulate around blood vessels and infiltrate the surrounding brain parenchyma.

Anaplastic meningiomas (WHO grade III) are highly aggressive tumors that resemble high-grade sarcomas or carcinomas.

Meningiomas mostly occur in adults.

Anaplastic ependymomas are a type of ependymoma characterized by increased cell density, high mitotic rates, necrosis, and less evident ependymal differentiation.

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.

Relating to the process of secretion, which is the release of substances from cells or glands.

Gangliogliomas are rare, slow-growing tumors that typically contain both neuronal and glial components, often found in the temporal lobe of the brain.

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.

The most common type of embryonal neoplasm is medulloblastoma, which accounts for 20% of pediatric brain tumors.

Most commonly in the pineal and suprasellar regions along the midline.

Children and young adults.

Most meningiomas are easily separable from the underlying brain, although some infiltrate the brain, which is associated with an increased risk of recurrence.

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.

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.

Metastatic tumors typically present as sharply demarcated masses, often located at the gray-white junction, and can elicit edema.

Treatment options for Germ Cell Tumors typically include surgery, chemotherapy, and radiation therapy, depending on the tumor type and location.

Oligodendrogliomas are mainly located in the cerebral hemispheres, particularly in the frontal or temporal lobes.

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.

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.

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.

Rosenthal fibers are elongated, eosinophilic structures found in pilocytic astrocytomas, indicative of the tumor's astrocytic origin.

Tumors of similar histologic type and poor differentiation that can be found elsewhere in the nervous system, related to Medulloblastoma.

Meningiomas are tumors that arise from arachnoid meningothelial cells, primarily occurring in adults.

Mutations in NF2 are more common in tumors with fibroblastic, transitional, and psammomatous growth patterns.

Astrocytomas are a type of glioma that resemble astrocytes, which are star-shaped glial cells in the brain.

An aggressive disease characterized by multiple tumor nodules within the brain parenchyma, often associated with immunosuppressed individuals and linked to the Epstein-Barr virus.

The superficial temporal lobe.

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.

Primary CNS tumors are classified as Gliomas, Neuronal Tumors, Embryonal (Primitive) Neoplasms, Germ Cell Tumors, Meningiomas, and Lymphoma.

Anaplastic astrocytomas are characterized by regions that are more densely cellular, greater nuclear pleomorphism, and the presence of mitotic figures.

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.

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.

Multiple meningiomas that occur in association with eighth-nerve schwannomas or glial tumors.

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.

Diffuse astrocytomas are commonly located in the cerebral hemispheres.

Metastatic tumors are secondary tumors that originate from primary cancers, mostly carcinomas, and account for one fourth to one half of intracranial tumors.

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.

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.

Pilocytic astrocytomas are a type of brain tumor characterized by the presence of hair-like cells and Rosenthal fibers.

Hair-like cells are a distinctive feature of pilocytic astrocytomas, contributing to their unique histological appearance.

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.

Whorled clusters of cells without visible cell membranes that sit in tight groups.

Elongated cells and abundant collagen deposition between.

Oligodendrogliomas are a type of glioma that resemble oligodendrocytes, which are glial cells that produce myelin in the central nervous system.

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.

The most common primary sites for metastatic tumors are the lung, breast, skin (melanoma), kidney, and gastrointestinal tract, accounting for about 80% of cases.

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.

Oligodendrogliomas are associated with deletions of chromosomes 1p and 19q, which make them highly responsive to chemotherapy and radiotherapy.

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.

Meningiomas are well-defined dura-based masses that do not invade the brain, although they may extend into the overlying bone.

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.

Gangliogliomas are mixed neuronal-glial tumors that often occur in the temporal lobe and are composed of both ganglion cells and glial cells.

They are relatively well defined compared to glial neoplasms but not as discrete as metastases.

Shares features of the syncytial and fibroblastic types.

Common presentations of Diffuse astrocytomas include seizures, headaches, and focal neurologic deficits.

Well-demarcated margins suggest a clear boundary between the tumor and surrounding tissue, which can be associated with a better prognosis in metastatic melanoma.

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.

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.

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.

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.

In the cerebellum, third ventricle, optic pathways, spinal cord, and occasionally in the cerebral hemispheres.

Activating mutations in the serine-threonine kinase BRAF.

A low-grade childhood tumor that grows slowly and has a good prognosis after resection, often manifesting as a seizure disorder.

The three histologic groups of astrocytomas are well-differentiated astrocytoma (grade II), anaplastic astrocytoma (grade III), and glioblastoma (grade IV).

The common types of Germ Cell Tumors include teratomas, seminomas, and non-seminomatous germ cell tumors, each with distinct characteristics and treatment approaches.

Oligodendrogliomas primarily affect individuals in their fourth and fifth decades of life.

Lower-grade astrocytomas are characterized by mutations of IDH1 and IDH2.

The most common primary CNS germ cell tumor is germinoma.

Germ Cell Tumors represent 0.2% to 1% of brain tumors.

It has a relatively poor response rate to treatment.

The age spectrum is relatively wide, with more cases occurring after age 60.

It accounts for 1% of intracranial tumors.

At the microscopic level, the boundary between metastatic tumors and brain parenchyma is sharp, often accompanied by surrounding reactive gliosis.