Hypertrophic osteopathy is a bone disease secondary to cancer in the lungs.
Symptoms include stiffness and warm, firm swelling of the legs, and signs of lung disease such as coughing and difficulty breathing.
The most common cause in dogs is primary or metastatic pulmonary neoplasia.
[5] One theory is that hypertrophic osteopathy is caused by increased blood flow to the ends of the legs, overgrowth of connective tissue, and then new bone formation surrounding the bones.
The condition may reverse if the lung mass is removed or if the vagus nerve is cut on the affected side.