Major characteristics of the INA6 model of MBD. (A) X-ray imaging of the various arbitrary stages (stage 1-4) of plasmacytoma formation. (B) Gross (left), x-ray (center), and histologic (right) appearance of a high grade plasmacytoma and associated bone destruction. The histology shows the fibula with the tumor (T), bone marrow (BM), and cortical bone (B) labeled. (C) The 3-dimensional μCT renderings of contralateral (unaffected left) and engrafted (affected middle) proximal tibias showing focal OLs penetrating deep into the cortices (arrowheads). Axial reconstructions at levels A and B of the affected tibia are presented (right panels) demonstrating the depth of the lesions. (D-E) Histologic analysis of contralateral (D) and engrafted (E) knee joints demonstrating infiltration and disruption of the growth plate architecture. (F) Staining of bone marrow preparations from engrafted long bones with human-specific anti–CD138 antibody (top), demonstrating frequent CD138⁺ cells. Nuclei are counterstained with 4′,6-diamidino-2-phenylindole. Slides were examined using a Nikon Eclipse 800 upright microscope fitted with a Nikon DXM1200F digital camera. (F) Gross appearance of engrafted and contralateral tibias (bottom), demonstrating displacement of hematopoiesis. Representative images of n = 10 mice per group; experiment was performed twice.