Synchronous multifocal osteosarcoma involving the skull presenting with intracranial hemorrhage -case report-.

A 40-year-old man presented with a rare case of synchronous multifocal osteosarcoma involving the skull associated with intracerebral hemorrhage, manifesting as sudden headache and left homonymous hemianopia. Computed tomography revealed a skull tumor in the right occipital bone and intracerebral hemorrhage in the right occipital lobe. Gross total resection of the skull tumor with hematoma was performed. The histological diagnosis was osteosarcoma. The tumor cells had invaded into the surrounding brain parenchyma, resulting in intracerebral hemorrhage.