astrocytoma

n. tumor which is composed of astrocytes and forms in the brain or nervous system (Medicine)

Astrocytomas are primary intracranial tumors derived from astrocytes cells of the brain. They may arise in the cerebral hemispheres, in the posterior fossa, in the optic nerve, and rarely, the spinal cord. The WHO has given a four point scale depending on the histologic grade of the tumor (see below). This article focuses on the well-differentiated (Grade 2) astrocytoma. For grade 1 and 4 astrocytomas, see respective article headings: Pathogenesis Well-differentiated astrocytomas constitute about 25 to 30% of cerebral gliomas. They have a predilection for the cerebrum, cerebellum, hypothalamus, pons, and optic nerve and chiasm. Although astrocytomas have many different histological characteristics, the most common type is the well-differentiated fibrillary astrocytoma. These tumors express glial fibrillary acidic protein (GFAP), which possibly functions as a tumor suppressor, and is a useful diagnostic marker in a tissue biopsy.
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Astrocytoma /as·tro·cy·to·ma/ a tumor composed of astrocytes; the most common type of primary brain tumor and also found throughout the central [more]Astrocytoma - Community and Resources

noun
type of brain tumour, consisting of star-shaped cells which develop slowly in the brain and spinal cord

[as-troe-sye-TOE-ma]
A tumor that begins in the brain or spinal cord in small, star-shaped cells called astrocytes.