Peculiar pattern of glial fibrillary acidic protein production in extracranial metastatic tumor cells of malignant astrocytoma.

An 83-year-old woman suffered from malignant astrocytoma originating in the temporal lobe. Autopsy revealed its extracranial metastasis to the liver, lung and bone marrow. The tumor tissue at the primary site was composed of plump, process-forming cells and small cells with scanty cytoplasm, and showed dural invasion. In the metastatic areas, most of the tumor cells were small cells, although proliferation of the plump cells in contact with perivascular connective tissue was marked, particularly in the liver. These plump cells were positively stained with antiserum to glial fibrillary acidic protein (GFAP), showing that the collagenous tissue was able to induce increased production of GFAP by the glial tumor cells.