Histological characterization of an ependymoma in the fourth ventricle of a cat

A tumour occupying the fourth ventricle in a 3-year-old cat was removed sur gically and characterized as a tanycytic ependymoma on the basis of histolo gical features of low cellularity, inconspicuous perivascular pseudo-rosett es and fascicular architecture. Immunohistochemical analysis of sections re vealed that the neoplastic cells were immunoreactive for glial fibrillary a cidic protein (GFAP), vimentin and S-100. The histological and immunohistoc hemical findings were similar to those of human tanycytic ependymoma, a sub classification of ependymoma not previously described in domestic species. (C) 1999 W.B. Saunders Company Limited.