Dandy Walker-like malformation in an adult cat with seizures: clinical description and MRI characteristics.

Case summary: A 2-year-old male neutered domestic shorthair cat was referred for investigation of a 10-month history of self-limiting, generalised tonic-clonic seizures. The cat was reported to be normal interictally but had always had a static abnormal gait. General physical examination was unremarkable. Neuroanatomical localisation was compatible with a diffuse cerebellar and diffuse forebrain lesion. Complete blood count, biochemistry, bile acid stimulation test, urinalysis, cisternal cerebrospinal fluid (CSF) analysis, Toxoplasma gondii serology and T gondii polymerase chain reaction in CSF were all unremarkable. MRI revealed an abnormal caudal fossa, absent cerebellar vermis and small cerebellar hemisphere with distension of the fourth ventricle. There were no forebrain abnormalities identified in the MRI or CSF changes that could justify the seizures. Considering the clinical presentation, the cat's neurological examination and MRI features, a presumptive diagnosis of Dandy Walker-like malformation (DWLM) and epilepsy of unknown aetiology was made. Relevance and novel information: This is the first case report of an adult cat diagnosed with cerebellar malformation resembling DWLM and concomitant seizures, its MRI characteristics and long-term follow-up. The 3-year follow-up consultation revealed static neurological status with 2-4 seizures per year. The cat's quality of life remained good at the time of writing.