Metaplastic bone formation in the cartilage plate (CT). (A) The newly-formed bone marrow cavity (MC) is encircled by calcified bony trabeculae (TR). This portion is further shown in B (hematoxylin and eosin staining, ×100). (B) Photograph shows calcified bony trabeculae (TR) stained by Von-Kossa (100). Immunohistochemistry staining detected hematopoietic CD34+ cells (arrows in upper rectangle) and CD68+ macrophages (arrows in lower rectangle) in the marrow cavity (MC).