Papillary Ependymoma

Abstract: The authors report a case of carcinoma of the choroid plexus and review the 22 cases reported since 1844 that adhere to the criteria for primary choroid plexus carcinoma. Two-thirds of the tumors are found in children and all of these are located in the lateral ventricles. In adults most of the tumors are present in the fourth ventricle. Differentiation of this neoplasm from papillary ependymomas, choroid plexus papillomas, secondary carcinomas, and "collision tumors" is discussed.

Abstract: Twenty-six ependymal and 15 choroid plexus tumors were examined with monoclonal antibody against cytokeratin using the avidin-biotin-peroxidase complex (ABC) technique. Serial sections were examined with antisera to glial fibrillary acidic protein (GFAP). In five ependymal tumors (one ependymoma, two papillary ependymomas, and two primitive neuroectodermal tumors [PNET] with ependymal cells), a variable number of cytokeratin-positive cells were present. Most tumor cells (except two PNET) were positive with GFAP antisera. Many cytokeratin-positive cells were present in all choroid plexus tumors. GFAP-positive cells were present focally in six of 11 papillomas and in one of four carcinomas. Although their staining patterns and distribution were clearly different, focal coexistence of cytokeratin and GFAP was observed in six papillomas and two ependymal tumors. Thus, some ependymal tumors (especially papillary ependymomas and occasional PNET) and many choroid plexus tumors have demonstrable positivity with antibody to cytokeratin, suggesting a transitional cell type with features of both ependyma and choroid plexus.

Abstract: An immunohistochemical study was performed on the paraffin sections of 25 tumors in the central nervous system (CNS) with prominent papillary configurations These tumors included seven metastatic papillary carcinomas, six choroid plexus tumors, four papillary ependymomas, two myxopapillary ependymomas, two papillary pituitary adenomas, two astroblastomas, one papillary meningioma, and one anaplastic astrocytoma with significant papillary changes The panel of antibodies applied included anti-glial fibrillary acidic protein (GFAP), anti-carcinoembryonic antigen (CEA), anti-vimentin (VM), anti-S-100 protein (S-100 P), anti-cytokeratin, and anti-prealbumin antisera All ependymomas and astroblastomas examined expressed both VM and GFAP, which were either absent or focally expressed in choroid plexus tumors In contrast, all choroid plexus tumors showed anti-cytokeratin immunoreactivity that was absent in the ependymomas and astroblastomas Five choroid plexus tumors also expressed S-100 P, thus differentiating them from metastatic carcinoma that showed negative immunostaining Anti-CEA antisera immunoreactivity was seen in six metastatic tumors, whereas none of the primary CNS tumors expressed CEA Prealbumin was expressed in four choroid plexus tumors and two metastatic tumors Immunohistochemical typing using a panel of antibodies has allowed the differentiation of most of the papillary tumors in the CNS examined in this study