Figure 2

Representative immunohistochemical staining of osteoblastic tumors. IHH showed nuclear and cytoplasmic staining in most osteoblastic neoplasms. Nuclear SP7 was largely absent in this group of tumors. Nuclear SOX9 was typically absent in osteoblastic tumors except rare chondroblastic osteosarcomas. Osteosarcomas expressed RUNX2 and frequently co-expressed TWIST1. IHH, Indian hedgehog; OBL, osteoblastoma; OO, osteoid osteoma; OS, osteosarcoma.