A female Bullmastiff with calvarial hyperostosis syndrome and concurrent hyperostotic changes affecting the mandible and cervical vertebrae

Abstract

An immature female Bullmastiff presented for assessment of swelling of the right dorsal orbital region, causing discomfort. Computed tomography showed osseous proliferation of the calvarium, frontal bone and concurrent unilateral osseous changes at the level of the left mandible. Ventral new bone formation and remodelling changes were noted between vertebrae C7 and T1. The vertebral bodies of C5, C6 and C7 were fused. Histopathology was consistent with calvarial hyperostosis syndrome. Subsequently, the dog developed neurological signs: proprioceptive ataxia and lower motor neuron ambulatory tetraparesis. Magnetic resonance imaging showed mild osseous spinal cord compression at C7 level. Calvarial hyperostosis syndrome described in this report is the first recorded case of a dog having concurrent hyperostotic changes affecting the calvarium, mandible and cervical vertebrae in a dog.