[Contribution of electron microscopy in the differential diagnosis of tumors of the meninges, brain and spinal cord].

Critical Evaluation of 200 tumours of meninges, brain and spinal cord showed that to be familiar with the ultrastructural features of meningioma and its variants was instrumental in differential diagnosis of other primary or secondary meningeal tumours (neurinoma, paraganglioma, xanthomatous and histiocytic tumours). A limited value of electron microscopy was found in astrocytoma and glioblastoma in contrast to its importance in low-differentiated ependymoma and oligodendroglioma. The examination had histogenetical and taxonomic values in medulloblastoma (CNS neuroblastoma and mixed tumours with a component featuring primitive neuroectodermal or neuroblastic differentiation). Ultrastructure was very important in the so-called primitive neuroectodermal CNS tumours where only the lack of conspicuous glial or neuroblastic differentiation confirmed the diagnosis. Electron microscopy was instrumental in rare primary CNS lymphomas as well as in some metastatic tumours.