Астроцитома: Мидың ісігі және диагностикасы

Astrocytoma is a type of brain tumor. Astrocytomas (also astrocytomata) 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. Within the astrocytomas, two broad classes are recognized in literature, those with:
Narrow zones of infiltration (mostly noninvasive tumors; e. g., pilocytic astrocytoma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma), that often are clearly outlined on diagnostic images
Diffuse zones of infiltration (e. g., high grade astrocytoma), that share various features, including the ability to arise at any location in the central nervous system, but with a preference for the cerebral hemispheres; they occur usually in adults, and have an intrinsic tendency to progress to more advanced grades. 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.

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. In the first stage of diagnosis the doctor will take a history of symptoms and perform a basic neurological exam, including an eye exam and tests of vision, balance, coordination, and mental status. The doctor will then require a CT scan and MRI of the patient's brain. During a CT scan, X rays of the patient's brain are taken from many different directions. These are then combined by a computer, producing a cross sectional image of the brain. For an MRI, the patient relaxes in a tunnel like instrument while the brain is subjected to changes of magnetic field. An image is produced based on the behavior of the brain's water molecules in response to the magnetic fields. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to identify. If a tumor is found, a neurosurgeon must perform a biopsy on it. This simply involves the removal of a small amount of tumor tissue, which is then sent to a neuropathologist for examination and grading. The biopsy may take place before surgical removal of the tumor or the sample may be taken during surgery. Grading of the tumor sample is a method of classification that helps the doctor to determine the severity of the astrocytoma and to decide on the best treatment options. The neuropathologist grades the tumor by looking for atypical cells, the growth of new blood vessels, and for indicators of cell division called mitotic figures.

There are no precise guidelines because the exact cause of astrocytoma is not known.

[[File:Management of IDH mutant glioma. png|thumb|Management of IDH mutant gliomas, with astrocytomas at center and right. Long time U. S. Senator Ted Kennedy (D MA) died of malignant glioma. University of Texas sniper Charles Whitman, who killed multiple people during a mass murder event in 1966, was diagnosed with astrocytoma post mortem. The Connally Commission investigating the shooting concluded the tumor "conceivably could have contributed to his inability to control his emotions and actions". Major League pitcher Dan Quisenberry was diagnosed with grade IV astrocytoma in January 1998. He died age 45 in 1998 in Leawood, Kansas. Richard Burns, winner of the 2001 World Rally Championship, was diagnosed with astrocytoma in 2003. Four years to the day after winning the World Rally Championship, on 25 November 2005, Burns died in Westminster, London, aged 34, after having been in a coma for some days as a result of his brain tumour. Professional wrestler Matt Cappotelli was diagnosed with a grade 2/3 astrocytoma in December 2005, scuttling plans to promote Cappottelli to the main WWE roster. Cappotelli, who won a contract with WWE through the third season of their reality program Tough Enough, was the Ohio Valley Wrestling Heavyweight Champion at the time of his diagnosis and vacated the title in February 2006 after confirming the tumor was cancerous. Cappotelli underwent successful surgery and chemotherapy, but was unable to return to active wrestling work. He did return to OVW as a trainer in 2013. He died on June 29, 2018.