Histopathology full
histopath report
right hind limb: two sections of distal tibia are examined. locally extensively replacing the medullary cavity and segmentally infiltrating and replacing the cortical bone of the distal tibia is a densely cellular, poorly demarcated, unencapsulated, infiltrative mass composed of dense haphazard bundles and streams. Neoplastic cells multifocally border irregular spicules of hypocellular homogenous eosinophilic, variably mineralized material (osteoid). The cells are plump and spindled with indistinct cellular borders and a small to moderate amount of wispy eosinophllic cytoplasm. the nuclei are oval to elongate with finely stippled to hyperchromatic chromatin, and zero to three variably distinct nucleoli. Anisocytosis and anisokaryosis are moderate, and there are 8 mitotic figures in ten 400x fields. there are occasional scattered multinucleate neoplastic cells with up to 6-8 nuclei (osteoclasts). The infiltrated cortical bone is segmentally discontinuous, scalloped, and fragmented, where it is bordered by the mass or osteoclasts (osteolysis). The disrupted cortical bone is multifocally bordered by anastomosing trabeculae of woven bone (periosteal new bone), intermingled with periosteal fibrosis and edema.
right popliteal lymph node: two sections of lyph node are entirely processed and examined. there are hyperplastic primary and occasional secondary cortical follicles which mildly compress the surrounding thin fibrous capsule. The medulla and subcapsular and paratrabecular sinuses are expanded by moderate to large numbers of foamy macrophages, with fewer hemosiderophages, erythroctes, neutrophils, plasma cells, and lymphocytes. The medulla is mildly edematous.
Microsopic findings: right hind limb, distal tibia: osteosarcoma