Which neoplasm is most commonly found in the appendicular skeleton of dogs and cats?

Osteosarcoma is the most commonly found neoplasm in the appendicular skeleton of dogs and cats due to its aggressive nature and predilection for long bones, particularly in larger breed dogs. This type of cancer originates from osteoblasts, the cells responsible for bone formation, and often leads to rapid bone destruction and the formation of a mass.

In dogs, osteosarcoma typically manifests in the forelimbs or hindlimbs, with the distal radius, proximal humerus, and distal femur being common sites. Its tendency to metastasize, particularly to the lungs, is significant, highlighting the importance of early detection and intervention. In contrast to the other types of cancers listed, osteosarcoma is far more common in the appendicular skeleton, while lymphomas, sarcomas, and chondrosarcomas would more typically be found in different anatomical locations or present with varying characteristics. Understanding these specifics is crucial for accurate diagnosis and effective management in veterinary oncology.