Hypertrophic osteopathy is a diffuse periosteal proliferative condition of long bones in dogs secondary to neoplastic or infectious masses in the thoracic or abdominal cavity. The exact pathogenic mechanism is unknown, but periosteal vascularity is reduced.
Clinical signs include lameness, long-bone pain, and signs secondary to body cavity masses. Radiography reveals the primary masses and peripheral bone reactions.
Treatment includes thoracic or abdominal surgery to remove masses and unilateral vagotomy to block the neurovascular reflex associated with bone changes.