(A-B) Pulmonary dissemination of matrigel following bone marrow and tail vein injection at 1 minute post-injection (PAS, 20X). (C) Histologic section of lung tissue immediately following bone marrow injection, demonstrating embolus of osteosarcoma tumor cells suspended in Matrigel, with surrounding platelets (PAS, 20X). (D) Small pulmonary foci of osteosarcoma at 2 months following bone marrow injection (PAS, 20X). (E-J) Representative gross photographs and H&E sections of lungs with pulmonary metastases in nude mice injected with osteosarcoma cells via the bone marrow cavity, and tail vein.