Cervicothoracic syringohydromyelia associated with a prosencephalic mass in a dog

A five-year-old, female, neutered boxer, with neuroanatomical signs consistent with a C1-C5 myelopathy, was diagnosed with a prosencephalic mass and associated severe cervicothoracic syringohydromyelia. After treatment with corticosteroids and lomustine, neurological examination was normal. Imaging repeated three months later showed significant reduction in both the size of the mass and the syringohydromyelia. To the authors' knowledge, this is the first reported case of a dog with syringohydromyelia secondary to a rostral brain mass that had clinical signs on presentation solely due to the syrinx, and the first reported case in a dog of partial resolution of syringohydromyelia after treatment solely with chemotherapy.