Email comments/questions to [email protected], fax 800-556-3288, or log on to www.VetLearn.com Osteosarcoma (OSA) is the most common primary bone tumor of the appendicular skeleton in dogs. Chondrosarcoma (CSA), fibrosarcoma (FSA), and hemangiosarcoma (HSA) are also considered primary bone tumors, although they are diagnosed much less frequently. Other tumors with skeletal involvement, s...