ASTROCYTOMA

WHO Grade II, progresses to higher grades

Cell of Origin: ASTROCYTE

Synonyms: diffuse astrocytoma, "ordinary" astrocytoma

Common Locations: cerebral hemispheres, in children in the pons ("brainstem glioma")

Demographics: 4th and 5th decades (30's and 40's)

Histology: ill-defined, diffusely infiltrating, overrun (trap) neurons, enlargement but not destruction of the invaded structures, mitoses, vascular proliferation, and necrosis are not present

Special Stains: GFAP+ (Glial Fibrillary Acidic Protein)

Progression : naturally progress to anaplastic astrocytoma, and then to glioblastoma

Radiology: The lesion is usually recognized by causing expansion of the infiltrated portion of the cerebrum or brainstem. Mass effect may be minimal for the overall size of the signal/attenuation abnormality, and the lesion may be surprising large at the time of presentation with minimal symptoms. Regions of signal and attenuation change usually represent the neoplasm itself - since the intact blood-brain-barrier does not cause enhancement nor vasogenic edema. Hemorrhage is rare, however, calcification can occur. The tumor tends to follow white-matter tracts and may cross the corpus callosum, or follow the peduncles to/from the brainstem.

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