Hypertrophic osteopathy in a dog associated with intra-thoracic lesions: a case report and a review

This paper reviews hypertrophic osteopathy and describes one case report. Hypertrophic osteopathy is a rare pathologic disease process and is observed secondary to a mass in the thorax. In response to the presence of a mass(es), nonoedematous soft tissue swellings and a diffuse periosteal new bone formation develop in all four limbs. The result is mild to severe lameness. A twelve-year-old sexually intact female Cocker spaniel had undergone radical mastectomy on both sides in another veterinary hospital about two years before presentation in our hospital with lameness of both hind limbs. Pain and soft tissue swelling on the distal parts of extremities were determined in clinical examinations. Radiographs revealed periosteal new bone formation on all the long bones of all four limbs, pelvis and sternum; additionally, intrathoracic masses were observed. Euthanasia was performed five months later. Macroscopic examinations of the lungs revealed diffuse and exuberant masses with grizzled whitish cross-sectional colour and with necrotic and haemorrhagic foci. The radius-ulna, tibia, metacarpal and metatarsal bones of both limbs were examined and collected after the necropsy examination. Bone specimens were thicker and the outer surfaces seemed to be rough. At the histopathologic examination of the lung tissue, ovoid or round shaped and hyperchromatic nucleated diffuse anaplastic mammary gland epithelial cells were observed. According to these findings, these masses were diagnosed as the metastasis of malignant mixed tumours.