A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secondary tumors, which most commonly have spread from tumors located outside the brain, known as brain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the size of the tumor and the part of the brain that is involved. Where symptoms exist, they may include headaches, seizures, problems with vision, vomiting and mental changes. Other symptoms may include difficulty walking, speaking, with sensations, or unconsciousness.
A glioma is a type of tumor that starts in the glial cells of the brain or the spine. Gliomas comprise about 30 percent of all brain tumors and central nervous system tumours, and 80 percent of all malignant brain tumours.
Oligodendrogliomas are a type of glioma that are believed to originate from the oligodendrocytes of the brain or from a glial precursor cell. They occur primarily in adults but are also found in children.
Glioblastoma, previously known as glioblastoma multiforme (GBM), is the most aggressive and most common type of cancer that originates in the brain, and has very poor prognosis for survival. Initial signs and symptoms of glioblastoma are nonspecific. They may include headaches, personality changes, nausea, and symptoms similar to those of a stroke. Symptoms often worsen rapidly and may progress to unconsciousness.
Astrocytoma is a type of brain tumor. Astrocytomas originate from a specific kind of star-shaped glial cell in the cerebrum called an astrocyte. This type of tumor does not usually spread outside the brain and spinal cord and it does not usually affect other organs. After glioblastomas, astrocytomas are the second most common glioma and can occur in most parts of the brain and occasionally in the spinal cord.
The International Classification of Diseases for Oncology (ICD-O) is a domain-specific extension of the International Statistical Classification of Diseases and Related Health Problems for tumor diseases. This classification is widely used by cancer registries.
Pilocytic astrocytoma is a brain tumor that occurs most commonly in children and young adults. They usually arise in the cerebellum, near the brainstem, in the hypothalamic region, or the optic chiasm, but they may occur in any area where astrocytes are present, including the cerebral hemispheres and the spinal cord. These tumors are usually slow growing and benign, corresponding to WHO malignancy grade 1.
Ganglioglioma is a rare, slow-growing primary central nervous system (CNS) tumor which most frequently occurs in the temporal lobes of children and young adults
Gliomatosis cerebri is a rare primary diffuse brain tumor that has a poor prognosis. It is defined by the World Health Organization as a diffusely infiltrating glial tumor impacting at least three cerebral lobes, mostly with bilateral involvement of the cerebral hemispheres and/or deep gray matter. These malignancies consist of infiltrative threads that spread quickly and deeply into the surrounding brain tissue, or into multiple parts of the brain simultaneously, making them very difficult to remove with surgery or treat with radiation. It is distinguished histopathologically by the infiltration of malignant astrocytic components into the surrounding neuropil. Gliomatosis cerebri behaves like a malignant tumor that is very similar to glioblastoma.
A nerve sheath tumor is a type of tumor of the nervous system which is made up primarily of the myelin surrounding nerves. From benign tumors like schwannoma to high grade malignant neoplasms known as malignant peripheral nerve sheath tumors, peripheral nerve sheath tumors include a range of clearly characterized clinicopathologic entities. A peripheral nerve sheath tumor (PNST) is a nerve sheath tumor in the peripheral nervous system. Benign peripheral nerve sheath tumors include schwannomas and neurofibromas.
Choroid plexus tumors are a rare type of cancer that occur from the brain tissue called choroid plexus of the brain. Choroid plexus tumors are uncommon tumors of the central nervous system that account for 0.5–0.6% of intracranial neoplasms in people of all ages. Choroid plexus papilloma, atypical choroid plexus papilloma, and choroid plexus carcinoma are the three World Health Organization types for these neoplasms. Children under the age of five account for 10% of cases of choroid plexus tumors. In children and adults, respectively, the lateral ventricle and the fourth ventricle are common locations, About 5% of all choroid plexus tumors are located in the third ventricle. Along with other unusual places such the cerebellopontine angle, the Luschka foramen, or brain parenchyma, the third ventricle is a rare location for choroid plexus tumors. Together, atypical choroid plexus papilloma, and choroid plexus carcinoma make up around 25% of all choroid plexus tumors. Although there have been reports of third ventricle choroid plexus papillomas in people in their fifth decade of life, only 14% of choroid plexus tumors are reported to arise in infants. Most findings indicate that choroid plexus tumors have no sex predilection.
Glial tumor is a general term for numerous tumors of the central nervous system, including astrocytomas, ependymal tumors, Oligodendroglioma, and primitive neuroectodermal tumors. The World Health Organization (WHO) classifies tumors into different categories according to severity and recurrence.The first tumor classified as grade I is called pilocytic astrocytoma and it is most commonly observed in children rather than adults. The next tumor is never common in the Dns called diffuse astrocytoma and it is considered a grade II, they are benign, or noncancerous, but can become malignant, meaning cancerous, as the tumor progresses. Grades III and grade IV are considered malignant astrocytomas. Anaplastic astrocytomas are considered by the WHO to be a grade III astrocytoma and Glioblastoma is a grade IV both are referred to high-grade glial tumors.
Gliosarcoma is a rare type of glioma, a cancer of the brain that comes from glial, or supportive, brain cells, as opposed to the neural brain cells. Gliosarcoma is a malignant cancer, and is defined as a glioblastoma consisting of gliomatous and sarcomatous components. Primary gliosarcoma (PGS) is classified as a grade IV tumor and a subtype of glioblastoma multiforme in the 2007 World Health Organization classification system (GBM). Because of a lack of specific and clear diagnostic criteria, the word "gliosarcoma" was frequently used to refer to glial tumours with mesenchymal properties, such as the ability to make collagen and reticulin.
The WHOclassification of tumours of the central nervous system is a World Health Organization Blue Book that defines, describes and classifies tumours of the central nervous system (CNS).
The giant-cell glioblastoma is a histological variant of glioblastoma, presenting a prevalence of bizarre, multinucleated giant cells.
Papillary tumors of the pineal region were first described by A. Jouvet et al. in 2003 and were introduced in the World Health Organization (WHO) classification of central nervous system in 2007. Papillary Tumors of the Pineal Region are located on the pineal gland which is located in the center of the brain. The pineal gland is located on roof of the diencephalon. It is a cone-shaped structure dorsal to the midbrain tectum. The tumor appears to be derived from the specialized ependymal cells of the subcommissural organ. Papillary tumors of the central nervous system and particularly of the pineal region are very rare and so diagnosing them is extremely difficult.
Central neurocytoma (CNC) is an extremely rare, ordinarily benign intraventricular brain tumour that typically forms from the neuronal cells of the septum pellucidum. The majority of central neurocytomas grow inwards into the ventricular system forming interventricular neurocytomas. This leads to two primary symptoms of CNCs, blurred vision and increased intracranial pressure. Treatment for a central neurocytoma typically involves surgical removal, with an approximate 1 in 5 chance of recurrence. Central neurocytomas are classified as a grade II tumor under the World Health Organization's classification of tumors of the nervous system.
Anaplastic oligodendroglioma is a neuroepithelial tumor which is believed to originate from oligodendrocytes, a cell type of the glia. In the World Health Organization (WHO) classification of brain tumors, anaplastic oligodendrogliomas are classified as grade III. In the course of the disease, it can degenerate into highly malignant oligodendroglioma, grade IV. The vast majority of oligodendrogliomas occur sporadically, without a confirmed cause and without inheritance within a family.
Angiocentric glioma (AG) refers to a rare neuroepithelial tumor when the superficial brain malignant cells enclose the brain vessels, commonly found in children and young adults. Initially identified in 2005 by Wang and his team from the University of Texas, AG was classified as Grade I by 2007 WHO Classification of Tumors of the Central Nervous System due to its benign clinical behavior, low proliferation index, and curative properties. AG primarily affects children and young adults at an average initial diagnosis age of 16 years old. Over 85% AG patients experience intractable seizures since childhood, especially partial epilepsy.
The WHO Classification of Tumours, more commonly known as the WHO Blue Books, is a series of books that classify tumours. They are compiled by expert consensus and published by the World Health Organization's (WHO) International Agency for Research on Cancer (IARC). They appear in print and online in a series of 15 books, each of which focuses on a major tumour group and defines the cause, mechanism, signs and symptoms, basic structure, diagnosis, epidemiology and outcomes of up to 300 types of tumours.
