Clinical Findings and Outcome in 30 Dogs with Presumptive or Confirmed Nerve Sheath Tumors

Simple Summary: Nerve sheath tumors (NSTs) are well-recognized tumors of the nervous system, but there is relatively limited information about these tumors in dogs. This study describes a group of dogs with NSTs affecting the nerves associated with the head or the spinal cord. Thirty dogs were included, 25 with a presumptive diagnosis and five with a confirmed diagnosis. Eight dogs had NSTs affecting one or more nerves of the head including five where the tumor caused compression of the brain. Six involved the trigeminal nerve. Twenty-two dogs had tumors affecting one or more spinal nerves with the majority affecting the nerves of a front limb. In 13 of the 22 dogs, the tumor caused compression of the spinal cord. The outcome was poor overall. Among the dogs alive at least 1 week after diagnosis, the survival time ranged from weeks to years. All dogs were eventually euthanized because of disease progression. While there was a broad overlap between tumor locations, survival was generally longer for dogs without compression of the spinal cord or brain. The results are limited by the small number of dogs with a confirmed diagnosis but still expand what is known about NSTs in dogs and highlight the need for more information on predictors of outcome. Nerve sheath tumors (NSTs) are well-recognized primary nervous system tumors, but there is relatively limited information in dogs including comparison of NSTs in different anatomical locations. This retrospective study describes the clinical features and outcomes in a group of dogs with NSTs affecting the cranial nerves or spinal nerves. Thirty dogs were included, 25 with a presumptive diagnosis and five confirmed by histopathologic analysis. Seven dogs also had cytology of tumor samples, which were supportive of the NST diagnosis in four. Eight dogs had cranial nerve-associated NSTs, with six involving the trigeminal nerve. Twenty-two dogs had spinal nerve-associated NSTs including 13 invading the spinal canal and nine peripheral to the spinal canal, with the majority affecting nerves or nerve roots of the brachial plexus. The prognosis was poor, with dogs being euthanized eventually because of disease progression. Among dogs alive 1 week after diagnosis, the median survival time was 4 months but ranged from 2 weeks to >2 years. While there was a broad overlap between NST locations, survival was generally longer for dogs without spinal canal or intracranial involvement. The results expand available information on NSTs in dogs but should be interpreted with caution given the small number of dogs with a definitive diagnosis. Further investigation is warranted to determine how tumor location, invasiveness, and treatments pursued impact outcome.