Gemistocytic astrocytoma

• i. One of the forms of WHO grade II astrocytomas (fibrillary, protoplasmic, and gemistocytic)
  • 1. most astrocytomas are the fibrillary type with a dense network of fine branching cytoplasmic processes
  • 2. protoplasmic astrocytomas are usually located superficially and composed of cells with small round nuclei and scanty perinuclear cytoplasm
  • 3. gemistocytic astrocytomas have abundant glassy deep pink cytoplasm and eccentrically placed nuclei
    • a. NOTE: gemistocytic astrocytomas have a slightly poorer prognosis than other astrocytomas
    • b. NOTE: most astrocytomas and particularlay gemistocytic astrocytomas show immunoreactivity for glial fibrillary acidic protein (GFAP) and S-100 protein but GFAP immunoreactivity is scant in protoplasmic astrocytomas