case_images: PMC4629594_01
case_images: Mediolateral radiograph shows a destructive bone lesion with pathological fracture of the proximal third of the humerus. The tumor is densely sclerotic, containing a considerable amount of mineralized osteoid. Small picture in the inset shows gross appearance of the osteosarcoma, with destruction of the cortex and a soft tissue mass with osteogenic white areas.
case_images: OpenVetJ-4-1-g001.jpg
case_images: PMC4629594_01_OpenVetJ-4-1-g001.jpg
case_images: F1
case_images: Radiographs of the limb showed an osteolytic sclerosing lesion with irregular rim, mild periosteal reaction and irregular cortex, intramedullary extension and pathologic fracture of the metaphyseal area, severe invasion and complete detachment of the right humeral epiphysis (Fig. 1).
case_images: Fibroblastic osteosarcoma. Cytological specimen shows a moderately dense population of spindle cells isolated or arranged in small clusters with elongated scanty cytoplasm and plump oval nuclei. The nuclei contained evenly distributed chromatin and small nucleoli. Few osteoblasts and little production of bone matrix were detectable in the specimens examined (40x).
case_images: OpenVetJ-4-1-g002.jpg
case_images: PMC4629594_01_OpenVetJ-4-1-g002.jpg
case_images: F2
case_images: FNA from the mass yielded a moderately cellular sample composed of loosely cohesive groups or single spindle cells with basophilic cytoplasmic tails, oval nuclei with central prominent multiple nucleoli and mild anysokariosis (Fig. 2).
case_images: Fibroblastic osteosarcoma. The tumor shows a pattern of neoplastic mesenchymal cells producing osteoid, woven bone collagen with extensive osteoblastic differentiation. There are numerous fibroblastic cells associated with diffuse activation of osteoclastic reactive giant cells (H&E, 4x and 20x).
case_images: OpenVetJ-4-1-g003.jpg
case_images: PMC4629594_01_OpenVetJ-4-1-g003.jpg
case_images: F3
case_images: Where the tumor was more intensely osteogenic and sclerotic, the cells were rarer, and were small, with slender nuclei, dense chromatin and no mitoses (Fig. 3).