Solitary intracranial subdural osteoma: intraoperative findings and primary anastomosis of an involved cortical vein.

We report a patient with a intracranial subdural osteoma with a large cortical vein passing through the subdural calcified mass. A 60-year-old man presented with an approximately 3-year history of persistent headache. Computerized tomography (CT) scanning showed a homogeneous high-density nodule attached to the inner surface of the right frontal skull. Intraoperatively, the hard mass was found to be located in the intradural subarachnoid space. A large cortical vein passed through the subdural mass and was anastomosed in an end-to-end fashion after the excision of the segment involved by the tumor. The histopathologic examination showed lamellated bony trabeculae lined by osteoblasts and the underlying dura was uninvolved by the tumor cells.