Giant cell glioblastoma in veterinary neuropathology

mical studies were performed on a white- greyish mass, 2 cm in diameter, which had developed in thè right cerebral cortex of a 15-year-old male Schnautzer dog. The animai had seizures with an acute onset for thrée weeks before being submitted to clinical examination. The histological examination was routinely performed with H&E and PAS and revealed a pleomorphic population of atypical large giant cells, many of which multinucleated, a high mitotic index, a pseudopalisade arrangement at thè margin of small necrotic areas and peripheral glomerular-like features. Immunostaining was performed with polyclonal rabbit anti-cow S-100 protein, rabbit anti-cow GFAP and rabbit anti-human lysozyme. Immunostaining was also performed with monoclonal mouse anti-swine vimentin and mouse anti-sheep glutamine-synthetase as primary antibodies. Immunohistochemically, thè tumor showed only a few GFAP, S-100 protein and glutamine-synthetase positive cells, while almost ali thè neoplastic cells showed intense reactivity for vimentin, especially thè multinucleated giant cells. Immunoreactivity was not obtained with antibody anti- lysozyme. The morphological and immunohistological findings of thè tumor are characteristic of glioblastoma, reported as anaplastic astrocytoma in thè dog with an incidence ranging from 3% to 15% of neural neoplasms. These tumors seem to occur more commonly in adult brachycephalic breeds without sex predominance. Interestingly, as previously reported ', our studies show a strong similarity between this tumor and human giant celi glioblastomas. Its astrocytic origin and extremely lo\ leve! of differentiation were highlighted by a moderate reaction to GFAP, S-100 prore:" ir.d glutamine-synthetase and by an intense reaction to vimentin. The prese?.: sr_dv confirms thè presence of this particular variant of glioblastoma or ir.iT.ir..; is::ocvtoma and it is suggested that thè term "giant celi glioblastoma" be '." :._ie; .- :r.t classification of brain tumors in domestic animals. :es: ) K. Uchidaetal.: "Gian: C,-;: 3!: r^::-u