Diffuse idiopathic skeletal hyperostosis (DISH) and spondylosis deformans in purebred dogs: a retrospective radiographic study.

A retrospective radiographic study was performed to investigate the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and spondylosis deformans (spondylosis) in 2041 purebred dogs and to determine association with age, gender and breed. Four cases of DISH provided information on the appearance of canine DISH. The prevalence of DISH and spondylosis was 3.8% (78/2041) and 18.0% (367/2041), respectively. Of dogs with DISH, 67.9% (53/78) also had spondylosis, whereas 14.0% (53/367) of dogs with spondylosis also had DISH. Dogs with DISH and/or spondylosis were significantly older than those without spinal exostosis. The prevalence of DISH and spondylosis was 40.6% (28/69) and 55.1% (38/69), respectively, in Boxer dogs. Nineteen smaller breeds were not affected by DISH, but showed signs of spondylosis; only standard Poodles appeared not to be affected by either disorder. Radiography, computed tomography (CT), magnetic resonance imaging (MRI), and/or histopathology were used to investigate four DISH cases. It was concluded that spondylosis and DISH can co-occur in dogs. DISH has probably been previously under-diagnosed and mistaken for severe spondylosis. The diagnosis can be made using radiography, CT or MRI. On histology, DISH can be distinguished from spondylosis by the location (ventral longitudinal ligament) and extent of new bone formation.