“Maggie” is a 12 year old Bearded Collie who presented with a two month history of nasal discharge. A biopsy revealed a diagnosis of anaplastic sarcoma. An MRI was ordered to evaluate the extent of the disease and for radiation therapy planning. The MRI identified a large heterogeneously enhancing mass, predominately within the left half of the nasal cavities. There was extensive osseous destruction, invasion of the hard palate, nasal septum, and medial aspect of the left globe. The cribriform plate appeared intact, however, there was a focal, superficial area of altered signal intensity involving the rostral, dorsolateral aspects of the left side of the olfactory lobe, most consistent with edema. The left frontal sinus appears fluid filled, most likely a build up of mucinous discharge due to occlusion of the sinus by the mass.