[Ultrastructure of ependymoma myxopapillare]

The results of histological and ultrastructural investigations of a tumour of the type of myxopapillary ependymoma growing initially extradurally in the end-part of the vertebral canal are reported. The patient has been observed for 13 years. During the disease several recurrences and distant metastases outside the central nervous system were observed. Histological examinations were carried out of the primary tumour and recurrences or metastases and always an evident papillary structure of tissue was found with characteristic "oedematous" stroma. In submicroscopic investigations attention was called to the stroma and to the ultrastructure of neoplastic cells. Slit-like spaces with numerous microvilli protruding into their lumen were observed between the neoplastic cells lying pallisade-like on the surface of papillae. These slits seemed on cross-sections to be minute tubular structures. This submicroscopic feature was not paid attention to in two previous papers discussing the ultrastructure of myxopapillary ependymoma.