20.Jul 2023

Case of the month: 7-month-old Staffordshire bull terrier, presented for mild pain on touching the head, behavioral changes, and swelling of the cranial vault

Signalment and anamnesis

  • 7-month-old Staffordshire bull terrier, male-intact
  • patient presented for mild pain on touching the head, behavioral changes, and swelling of the cranial vault

For further clarification the following radiographs were taken:



Radiographic description

  • Radiographs show generalized hyperostosis of the cranium, characterized by significant thickening of the cranial vault, particularly in the region of the frontale bone, parietal bone, and occipital bone
  • There is also suspected sclerosis of the affected bone structures, with increased bone density and decreased transparency compared to normal bone tissue
  • The outer and inner surfaces of the affected bones show multiple irregular protrusions and depressions
  • However, there is no evidence of acute fractures or bony displacement
  • The mandibular bones are unremarkable


  • Calvarial hyperostosis syndrome


  • The patient was asymptomatic several months after diagnosis and conservative therapy


  • Calvarial hyperostosis in dogs is a pathological change of the cranial vault in which there is excessive thickening of the bone
  • It is a localized form of hyperostosis that is concentrated on the skull bone, particularly the calvarium, which is the upper part of the skull
  • Calvarial hyperostosis in dogs can have various causes. Genetic factors play a role. One example is the related craniomandibular osteopathy (CMO), a hereditary condition in certain breeds of dogs that causes abnormal bone development/hyperostosis in the cranial and mandibular regions. Another possible cause is an inflammatory disease such as osteomyelitis, in which infection of the skull occurs
  • Symptoms of calvarial hyperostosis can vary depending on severity and cause. Possible signs include behavioral changes, swelling or bumps on the top of the skull, pain when touching the head, and possibly neurological symptoms if the bone growth puts pressure on the brain
  • The diagnosis of calvarial hyperostosis in dogs is usually made by imaging techniques such as X-ray, CT (computed tomography) or MRI (magnetic resonance imaging). These allow detailed imaging of the bone changes and help rule out other possible causes. Bone biopsies are also used as a diagnostic tool for exclusion
  • Treatment of calvarial hyperostosis depends on the cause and severity. In most cases, medical/conservative therapy results in relief of inflammation and pain


Many thanks to Dr. ECVDI Thorsten Rick for this case report!

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