First report of oligodendroglioma in a sheep.

Oligodendrogliomas occur most commonly in the dog, but have also been reported in cattle, horses and cats. A 1-year-old sheep with neurological disturbances, including blindness, ataxia, circling and incoordination was referred to the veterinary clinic of Shahid Bahonar University of Kerman. Following euthanasia and necropsy, a soft, relatively well-demarcated mass was observed in the white and grey matter of the right cerebral hemisphere, close to the sylvian fissure in the right cerebral hemisphere. Microscopic examination revealed a sheet of densely packed tumour cells with hyperchromatic nuclei, lightly staining cytoplasm and characteristic perinuclear halo effect which is consistent with a diagnosis of oligodendroglioma. This is the 1st report of oligodendroglioma in sheep.