Signalment:8.5-year-old spayed female Pit Bull-type dog
History:The patient presented to a primary veterinary hospital in August 2020 for a history of grand mal seizures. The initial diagnostic work-up included magnetic resonance imaging (MRI). The MRI showed a T1-weighted mass in the left prosencephalon, which was diagnosed as a glial tumor. Treatment with levetiracetam (Keppra) was initiated. The patient was referred to two different veterinary neurologists and at the second neurologist, the neurologic examination was within normal limits, and serologic fungal testing was negative. Additional diagnostics, including CSF tap and biopsy were declined and the patient was treated with prednisone, Keppra, and radiation therapy. After a rapid clinical decline, the patient became obtunded in October 2020 and presented to a neurologist. The neurologic examination was remarkably abnormal, with vestibular ataxia, poor postural reactions, increased spinal reflexes, left head tilt, and positional rotary nystagmus with a fast phase to the right. The neuroanatomic localization suggested disease in the ascending reticular activating system (ARAS), left prosencephalon, and within the caudal fossa. An MRI was repeated. This imaging survey revealed a larger, fluid-filled mass with distinct cavitation. The left-sided neural parenchyma was expanded by fluid, causing shift and tentorial herniation. The owner elected euthanasia, and the brain was submitted for evaluation.