A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant (cancerous) 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 primary tumor that starts in the glial cells of the brain or spinal cord. They are cancerous but some are extremely slow to develop. 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 a 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.
Central neurogenic hyperventilation (CNH) is an abnormal pattern of breathing characterized by deep and rapid breaths at a rate of at least 25 breaths per minute. Increasing irregularity of this respiratory rate generally is a sign that the patient will enter into coma. CNH is unrelated to other forms of hyperventilation, like Kussmaul's respirations. CNH is the human body's response to reduced carbon dioxide levels in the blood. This reduction in carbon dioxide is caused by contraction of cranial arteries from damage caused by lesions in the brain stem. However, the mechanism by which CNH arises as a result from these lesions is still very poorly understood. Current research has yet to provide an effective means of treatment for the rare number of patients who are diagnosed with this condition.
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.
A blastoma is a type of cancer, more common in children, that is caused by malignancies in precursor cells, often called blasts. Examples are nephroblastoma, medulloblastoma, and retinoblastoma. The suffix -blastoma is used to imply a tumor of primitive, incompletely differentiated cells, e.g., chondroblastoma is composed of cells resembling the precursor of chondrocytes.
A gemistocyte is a swollen, reactive astrocyte.
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.
A brainstem glioma is a cancerous glioma tumor in the brainstem. Around 75% are diagnosed in children and young adults under the age of twenty, but have been known to affect older adults as well. Brainstem gliomas start in the brain or spinal cord tissue and typically spread throughout the nervous system.
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.
The concept of grading of the tumors of the central nervous system, agreeing for such the regulation of the "progressiveness" of these neoplasias, dates back to 1926 and was introduced by P. Bailey and H. Cushing, in the elaboration of what turned out the first systematic classification of gliomas.
In the following, the grading systems present in the current literature are introduced. Then, through a table, the more relevant are compared.
Medulloepithelioma is a rare, primitive, fast-growing brain tumour thought to stem from cells of the embryonic medullary cavity. Tumours originating in the ciliary body of the eye are referred to as embryonal medulloepitheliomas, or diktyomas.
Neuro-oncology is the study of brain and spinal cord neoplasms, many of which are very dangerous and life-threatening. Among the malignant brain cancers, gliomas of the brainstem and pons, glioblastoma multiforme, and high-grade astrocytoma/oligodendroglioma are among the worst. In these cases, untreated survival usually amounts to only a few months, and survival with current radiation and chemotherapy treatments may extend that time from around a year to a year and a half, possibly two or more, depending on the patient's condition, immune function, treatments used, and the specific type of malignant brain neoplasm. Surgery may in some cases be curative, but, as a general rule, malignant brain cancers tend to regenerate and emerge from remission easily, especially highly malignant cases. In such cases, the goal is to excise as much of the mass and as much of the tumor margin as possible without endangering vital functions or other important cognitive abilities. The Journal of Neuro-Oncology is the longest continuously published journal in the field and serves as a leading reference to those practicing in the area of neuro-oncology.
Fibrillary astrocytomas are a group of primary slow-growing brain tumors that typically occur in adults between the ages of 20 and 50.
Diffuse midline glioma, H3 K27-altered (DMG) is a fatal tumour that arises in midline structures of the brain, most commonly the brainstem, thalamus and spinal cord. When located in the pons it is also known as diffuse intrinsic pontine glioma (DIPG).
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.
Diffuse hemispheric glioma, H3G34 mutant (DHG) is a rare, high-grade, infiltrative WHO grade 4 brain tumor most often found in adolescents and young adults. The majority are found in the frontal, parietal, and temporal lobes.
