In humans, high-grade gliomas may infiltrate across the corpus callosum 
resulting in bihemispheric lesions that may have symmetrical, winged-like 
appearances. This particular tumor manifestation has been coined a "butterfly" 
glioma (BG). While canine and human gliomas share many neuroradiological and 
pathological features, the BG morphology has not been previously reported in 
dogs. Here, we describe the magnetic resonance imaging (MRI) characteristics of 
BG in three dogs and review the potential differential diagnoses based on 
neuroimaging findings. All dogs presented for generalized seizures and 
interictal neurological deficits referable to multifocal or diffuse forebrain 
disease. MRI examinations revealed asymmetrical (2/3) or symmetrical (1/3), 
bihemispheric intra-axial mass lesions that predominantly affected the 
frontoparietal lobes that were associated with extensive perilesional edema, and 
involvement of the corpus callosum. The masses displayed heterogeneous T1, T2, 
and fluid-attenuated inversion recovery signal intensities, variable contrast 
enhancement (2/3), and mass effect. All tumors demonstrated classical 
histopathological features of glioblastoma multiforme (GBM), including glial 
cell pseudopalisading, serpentine necrosis, microvascular proliferation as well 
as invasion of the corpus callosum by neoplastic astrocytes. Although rare, GBM 
should be considered a differential diagnosis in dogs with an MRI evidence of 
asymmetric or symmetric bilateral, intra-axial cerebral mass lesions with signal 
characteristics compatible with glioma.