Spinal arachnoid cysts in two shih tzu littermates.

Progressive ataxia and quadriparesis in two shih tzu littermates was found to be caused by almost identical, cranial cervical, spinal arachnoid cysts. The cysts were treated surgically by dural marsupialization via a dorsal laminectomy. One pup recovered uneventfully and remains clinically normal more than a year after surgery. The second pup made a slow and incomplete recovery before the signs worsened, necessitating euthanasia. Postmortem examination showed no evidence of the re-formation of the cyst.