A histopathological study of heterologous transplants of an unusual brain tumor.

astrocytes, as well as Hort.ega's triple impregna tions, did not reveal protoplasmic processes of the tumor cells, it was unlikely that the tumor was of neuro-ectodermal origin. The possibility of a mesodermal tumor, although suggested by a pen vascular arrangement of the tumor cells, found little support from the results of special technics. Azan stains revealed no collagen outside the vu culature, and Wilder silver impregnations demon strated no neticular fibnils other than in the pen vascular areas. Inasmuch as the clinical history extended oven 92years, it was felt that a melano matosis of the meninges should probably not be considered. This view was amplified further by the consistent lack of melanin in the tumor cells, by the notable rarity of melanomas among Negroes, especially in this age group, and by the demon stration of normal melanophores in the meninges infilt@ated by the tumor.' Several weeks after the biopsy, the child died. Autopsy revealed a brain tumor which evidently had originated from the site of operation and spread all over the right hemisphere, penetrating dura and skull, and in vading the subgalea at the area of the craniotomy. Histologically, the tumor presented the same features as were revealed at the biopsy. Particu larly impressive was the penivascular arrangement of the tumor cells where the neoplasm invaded the nerve tissues. It was considered that transplantation could lead to further information pertaining to : diagnosis. Therefore, tumor material, removed at surgery, was injected into a number of animals and 8-day-old embryonated chick eggs. When tnans planted into the anterior chamber of the guinea pig eye, the tumor grew rapidly. Within 4 weeks, the anterior chamber was completely filled in four of six animals. Secondary transplants were also obtained in the same species. Primary and secondary transplants in the chick embryos sun 1 Nettleship's preliminary diagnosis by frozen section was possible ganglioblastoma. The histopathological changes which are pro duced by the heterologous transplantation of hu man tumors have been studied for a number of years. Rather distinctive morphological altera tions may occur (3) and may be useful, on oc casion, in advancing the study of such trans planted neoplasms (Freeman and Zimmerman [92], and Willis [11]). On the other hand, ICniseley and Kernohan (7) feel that the method has distinct limitations in this regard. In a recent case, in which heterologous transplants of a human brain tumor were studied, certain morphologic features which …