CHONDROSARCOMA OF THE RADIUS WITH DISTANT METASTASIS IN A DOG

A 9-year-old castrated male Doberman Pinscher was admitted for evaluat ion of lameness of the left forelimb. Radiography and examination of b iopsy specimens revealed a moderately differentiated chondrosarcoma of the proximal portion of the radius. The dog was treated by local exci sion of the neoplasm, which involved resection of the radial head and proximal portion of the radius. Despite the large size of the dog and the weight-bearing forces exerted on the cubital joint, major problems with ambulation did not develop after surgery. Functional use of the limb returned slowly; however, substantial limb use was observed despi te the development of mild degenerative changes of the joint and migra tion of the humeroulnar articulation. Six months after surgery, metast asis of a widely disseminated, poorly differentiated chondrosarcoma to the subcutaneous tissues and thoracic and abdominal cavities was diag nosed. Local redevelopment of the chondrosarcoma in the area of the cu bital joint was not detected. Resection of the radial head and proxima l portion of radius may be considered a viable, alternative, limb-spar ing technique. The biologically aggressive nature of this chondrosarco ma of the appendicular skeleton indicated that additional information was needed before a reliable prognosis could be established for this d og with this tumor type. Reports of low rates of metastasis have been based on insufficient numbers of dogs to adequately or accurately dete rmine the long-term prognosis of dogs with chondrosarcoma of the appen dicular skeleton.