GLIOSARCOMA WITH FEATURES OF CHONDROBLASTIC OSTEOSARCOMA

Background. The occurrence of osteoid-chondral elements in gliosarcoma is extremely rare and has been reported in only two cases. A new, rar e case of gliosarcoma with osteosarcomatous differentiation in a 55-ye ar-old man and histogenesis of osteoid-chondral tissue in gliosarcoma is discussed. Methods. Surgically removed tumor tissues were examined immunohistochemically and electron microscopically, and a histologic e xamination was performed. Results. Immunohistochemical and electron mi croscopic studies confirmed the presence of glial, fibroblastic, and o steoid-chondral elements. A major part of the sarcomatous tissue was u ndifferentiated and stained only by vimentin. Some areas of osteoid-ch ondral tissue were positive for glial fibrillary acidic protein (GFAP) . Conclusions. These data suggest that osteoid-chondral elements came from the sarcomatous portion and GFAP positivity is not restricted to astrocytes and has been seen particularly in chondroid areas of non-gl ial tumors.