PRIMARY OSTEOSARCOMA OF THE CEREBRUM WITH IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL STUDIES - REPORT OF A CASE

A 57-year-old woman with primary intracerebral osteosarcoma is reporte d. The tumor was identified by computed tomography as a mass with hemo rrhage in the right parietal lobe. The surgical and pathological exami nations confirmed an osteosarcoma of intracerebral origin. She suffere d from repeated local recurrence of the tumor and died about 1 year af ter the onset. The pathological findings showed features of osteoblast ic osteosarcoma with numerous osteoclastlike multinucleated giant cell s. Immunohistochemically, tumor cells were positive for vimentin, and partially for actin. Multinucleated giant cells were reactive with vim entin and CD68 antibodies. Ultrastructurally, tumor cells were rich wi th rough endoplasmic reticulum. These findings are consistent with the histological features of skeletal or extraskeletal osteosarcoma. This is the third case of primary intracerebral osteosarcoma reported in t he literature and the first one analyzed ultrastructurally.