Archive Case #142: Canine Osteosarcoma

Clinical Clues

1. A large-breed dog develops progressive lameness in one forelimb over several weeks.
2. The owner reports local swelling near the distal radius.
3. Palpation of the site is very painful and the dog resists weight bearing.
4. Radiographs reveal an aggressive bone lesion with cortical destruction and new bone formation.
5. Thoracic imaging is recommended because this tumour commonly metastasises to the lungs.
6. Osteosarcoma is the most common primary bone tumour of dogs and often affects the appendicular skeleton.

Diagnosis

Canine Osteosarcoma

This case is most consistent with Canine Osteosarcoma because the dog has a painful aggressive bone lesion in a classic location for a large-breed appendicular tumour. The most important clues are the distal radial mass and radiographic pattern, which make a simple traumatic periosteal reaction less likely.

Educational Use

Vetdle archive cases are educational veterinary games for diagnostic reasoning practice. They do not provide veterinary advice, diagnosis, treatment, or professional medical guidance.