EMA in papillary ependymoma: The smooth luminal surface of this papillary ependymoma is highlighted by immunohistochemistry for EMA. This type of pattern can also be seen in ependymal canals in ependymomas. In addition, dots like cytoplasmic immunoreactivities are often seen in ependymomas. The expression of EMA in ependymoma, however, is highly variable between different tumors and different areas of the same tumor.

GFAP in papillary ependymoma: Ependymomas are typically positive for GFAP. This stain, however, cannot separate choroid plexus tumor from ependymoma as choroid plexus tumors are also positive for GFAP.