Astrocytoma

Astrocytomas are a type of cancer of the brain. They originate in a particular kind of glial cells, star-shaped brain cells in the cerebrum called astrocytes. This type of tumor does not usually spread outside the brain and spinal cord and it does not usually affect other organs. Astrocytomas are the most common glioma and can occur in most parts of the brain and occasionally in the spinal cord. Within the astrocytomas, two broad classes are recognized in literature, those with:Low grade astrocytoma of the midbrain (lamina tecti), sagittal T1-weighted magnetic resonance imaging after contrast medium administration: The tumor is marked with an arrow. The CSF spaces in front of the tumor are expanded due to compression-induced hydrocephalus internus.A pathological specimen of a gemistocytic astrocytomaMRI scans of an astrocytoma patient, showing tumor progression over the course of seven years Astrocytomas are a type of cancer of the brain. They originate in a particular kind of glial cells, star-shaped brain cells in the cerebrum called astrocytes. This type of tumor does not usually spread outside the brain and spinal cord and it does not usually affect other organs. Astrocytomas are the most common glioma and can occur in most parts of the brain and occasionally in the spinal cord. Within the astrocytomas, two broad classes are recognized in literature, those with: People can develop astrocytomas at any age. The low-grade type is more often found in children or young adults, while the high-grade type is more prevalent in adults. Astrocytomas in the base of the brain are more common in young people and account for roughly 75% of neuroepithelial tumors. Astrocytoma causes regional effects by compression, invasion, and destruction of brain parenchyma, arterial and venous hypoxia, competition for nutrients, release of metabolic end products (e.g., free radicals, altered electrolytes, neurotransmitters), and release and recruitment of cellular mediators (e.g., cytokines) that disrupt normal parenchymal function. Secondary clinical sequelae may be caused by elevated intracranial pressure attributable to direct mass effect, increased blood volume, or increased cerebrospinal fluid volume. A genome-wide pattern of DNA copy-number alterations (CNAs) has been uncovered, which is correlated with a patient’s survival and response to treatment. This pattern identifies among glioblastoma as well as lower-grade astrocytoma patients a subtype, where the CNA genotype is correlated with an approximately one-year survival phenotype. An X-ray computed tomography (CT) or magnetic resonance imaging (MRI) scan is necessary to characterize the extent of these tumors (size, location, consistency). CT will usually show distortion of third and lateral ventricles with displacement of anterior and middle cerebral arteries. Histologic analysis is necessary for grading diagnosis.