A 4 months old Golden retriever male dog was referred. By the history taking, it was kwon that the mass has been formed at the parietal region of the patient after fourth prevention inoculation. The appetite, urination and excretion were normal. The mass confirmation which was limited in the parietal region, did not seem to be enlargement of lymph node from physical examination palpation. Complete blood count and serum biochemical profiles were consistent with mild lymphocytosis, mild monocytosis, anisocytosis, regenerative anemia and elevated ALP, CPK. Survey radiographs indicated a mixed density in parietal region. We performed surgical resection and chemotherapy for cure and biopsy. Histological finding was periosteal fibrosarcoma. The application of cisplatin was topically used in operation site. Up to now the indication of recurrence is not visible.