[Immunohistochemical and ultrastructural studies of intracranial immature teratoma--a comparative observation on neuroblastoma, PNET and ependymal tumor, with a special reference to rosette structures].

Immature teratoma occurs occasionally in the brain of children and contains a large amount of immature neuronal tissue. These primitive neuronal components are a good target for studying the morphology of primitive neuroectodermal tumors, including neuroblastoma, ependymoblastoma, medulloepithelioma and so on. Primitive neural tubes are immunohistochemically and ultrastructurally studied in two cases of primary immature teratoma of the child brains, compared to true rosettes in a case of neuroblastoma, primitive neural tube in the fetal rat brain (9 to 13 days of gestational age). The study also extends to the pathology of PNET. Ultrastructurally the primitive neural tube like structures in two teratomas were virtually identical those of developing fetal rat brains and true rosettes in a neuroblastoma. However, these tubular structures are different from each other in immunohistochemistry. These differences are considered to reflect the different developmental lineage of the tumor cells, that is, neuroblastoma produces only neuroblastic cells, and primitive neural tubes in teratoma both neuroblastic and glioblastic cells. Rejuvenation of neuroblastoma cells seems to render a VIM-positivity of the tumor cells.