Bone Chondroblastoma : An Immunohistochemical and Ultrastructural Study

To elucidate the histogenesis of chondroblastoma, we examined seven cases of chondroblastoma immunohistochemically and ultrastructurally. Immunohistochemically, the majority of mononuclear tumor cells were positive for S-100 protein, but far fewer were Type II collagen-positive mononuclear tumor cells. This immunohistochemical pattern was similar to that of embryonal cartilage cells. Moreover, the ultrastructural features of mononuclear tumor cells closely resembled those of embryonal cartilage cells. Osteoclast-like multinucleate giant cells were confirmed to be histiocytic in nature and a reactive element. Our findings suggest that chondroblastoma develops from the remnant of embryonal cartilage