Suspected glioma in a 15 year old mixed breed dog

Princess, a 15-year-old FS mixed breed dog, presented to the Cornell University Small Animal Emergency Service for evaluation of generalized seizures. She was found that morning having a generalized seizure with no possibility of toxin ingestion and was taken to the local emergency clinic for evaluation. She was stabilized with fluids, valium and a loading dose of phenobarbital and transferred to the Cornell University Hospital for Animals that evening. Physical exam revealed facial twitches, decreased menace response OD worse than OS, concious proprioceptive (CP) deficits right hind worse than left hind, moderate osteoarthritis, nuclear sclerosis OU, and shaved areas where catheters had been placed previously. CBC and chemistry panel were within normal limits, and urinalysis demonstrated a urinary tract infection. Current medications included Clavamox 375mg PO BID for the urinary tract infection. Possible differential diagnoses include forebrain disease (degenerative, anomalous, neoplasia, infectious/inflammatory, trauma), metabolic abnormality, and toxin ingestion. Based on her age, presentation, and the normal bloodwork, Princess? primary differential was CNS neoplasia. She was taken to radiology for 3-view thoracic radiographs which were within normal limits and then MR imaging of her brain. A well-defined, contrast enhancing, circular lesion was identified in her left pyriform lobe. Although never biopsied, this lesion supported the differential diagnosis of neoplasia. It was presumed to be a glioma based on its singularity, shape, location and contrast enhancement on MRI. Possible palliative treatments included surgery, radiation therapy, chemotherapy, and steroids alone. Anti-convulsants would be added to any of these treatment protocols as Princess' chief complaint was seizures. Princess was maintained on prednisolone and felbamate, a very expensive anti-convulsant with fewer reported side effects than phenobarbital. She was given a prognosis of 2 weeks-2 months. Within three days from presentation, Princess was clinically normal, and has remained that way since. It is now 6 months from her diagnosis.