A case report of osteodystrophia fibrosa in a horse

A 7 years old male Kathiawari horse presented for necropsy revealed bilateral swelling of frontal bones below the eyes. Hyperphosphatemia and hypocalcaemia were noticed in serum biochemical examination. Radiographic examination revealed extensive osteolytic changes and severe bone resorption in the skull and long bones. On internal examination, mandible and maxilla of the skull were very brittle. Most of the long bones and ribs were porous and brittle. Histopathological examination revealed osteoclastic bone resorption characterized by lacunae containing osteoclasts and extensive replacement of bone with fibrous connective tissue. Masson's trichrome stain revealed decreased number of trabecular bone and extensive deposition of fibrous connective tissue. The case was diagnosed as osteodystrophia fibrosa based on history, physical and clinico-pathological findings.