[A histopathological study on a glioma with radiation necrosis and brain stem spongiform degeneration (author's...

A histopathological study on an autopsy case of 38-year-old female who had suffered from huge glioma and received radiation therapy as well as operation and chemotherapy was reported. The tumor mainly involved the right frontal lobe and partially invaded to the left cerebral hemisphere. Subarachnoidal dissemination of tumor cells was noticed in cerebellum, brain stem and spinal cord. Under the microscope the tumor was mainly consisted of astrocytic tumor cells, while oligodendrocytic ones and those with anaplastic or bizarre nuclei were observed among them. Though ependymomatous appearance was partially seen, no true rosette was found. From these findings the tumor was histologically diagnosed as anaplastic glioma. Simultaneously, there was massive coagulative necrosis which was limited to the irradiated area in the tumor tissue and surely attributable to irradiation. In addition, proliferation of gemistocytic astrocytes which was independent of glioma itself was widely observed in the field of irradiation. Another remarkable finding was spongiform degeneration which was located in the subpial area of brain stem including degenerative products of myelin sheaths and axons with neither inflammatory changes not gliosis. In some papers it is suggested that such a lesion has something to do with irradiation or chemotherapy. But in our case this lesion was found in non-irradiated area and no intramedullary injection of chemical agents was performed. Further, the distribution of this lesion was for the most part restricted to the domain of the pontine cistern which had been huge owing to stagnant hemorrhagic fluid. Therefore, it is highly probable that this lesion was caused by the abnormal pia-glial barrier.