33rd Annual Scientific Meeting proceedings

Introduction: Osteosarcomas are rare in horses and appear mostly on head and limbs. Literature shows surgical treatment alone is not being sufficient. Since radiation therapy is rather difficult to obtain in horses and very expensive, most horses are unfortunately submitted to euthanasia.

Case description: A 5 months old warmblood foal was admitted to the clinic for a rapid growing mass at the level of the left temporal region for 3 months. Biopsy performed by the referring veterinarian revealed diagnosis of osteosarcoma. Further examination showed no signs of metastasis visible on ultrasonographic and radiographic examination. No pain or neurologic symptoms were present. In order to evaluate the extend of the tumor and in preparation of surgery, CT-scan was performed.

Results: A large expansile bone lesion of 8 by 9 by 5 cm is present at the left dorsolateral aspect of the cranial volt resulting in destruction of the frontal and parietal bone (large defect of 2 by 4 cm) and secondary compression of the parietal lobe of the left hemisphere. Surgical excision was successful and no complications occurred during healing. Histopathology of the mass reconfirmed osteosarcoma. Although the remaining bone defect, wound healing was very good. Telephone follow-up with the owners confirm no relapse after 1 year.

Conclusion: Surgical treatment in osteosarcoma (without metastasis) can be successful if complete tumor removal can be achieved and can be considered when adjuvant therapy is not available.