derives from/develops from astrocyte astrocytoma cell A tumor cell composed of astrocytes; it is the most common type of primary brain tumor and is also found throughout the central nervous system. One classification groups astrocytomas according to their histologic appearance and distinguishes pilocytic, protoplasmic, gemistocytic, and fibrillary types. Another classification groups them in order of increasing malignancy as Grade I, Grade II, Grade III, and Grade IV types. BTO:0000100 BrendaTissueOBO astrocytic glioma cell astroglial neoplasm cell astroglial tumor cell astroglioma cell glioma cell