Ultrastructure of a composite glioma-sarcoma of the brain

The ultrastructural features of a composite glioma-sarcoma of the brain are described. Glial cells had short cytoplasmic processes, a highly developed rough endoplasmic reticulum and bundles of intracytoplasmic filaments 80–90 Å thick. The nucleus contained evenly distributed chromatin and spheroidal bodies up to 5000 Å in diameter. Mesenchymal cells had elongated cytoplasm, a rough endoplasmic reticulum with short cisternae, numerous lysosomes and groups of vesicles associated with the plasma membrane. Nuclei were elongated and contained spheroidal bodies similar to those observed in glial cells. The interstitial space contained abundant collagen fibers. The endothelial cells exhibited rows of pinocytotic vesicles and a well developed Golgi complex. The ultrastructural observations are considered confirmatory of the composite nature of these tumors. It is believed that the sarcomatous component originates in the hyperplastic endothelial cells.