[A case of solitary fibrous tumor in the cerebral convexity indicating its non-dural origin].

We report a case of solitary fibrous tumor (SFT) in the cerebral convexity, and present characteristic radiological and surgical findings to determine its origin. The patient was a 59-year-old man with mental dullness and mild gait disturbance. CT scan and MR images showed a highly enhanced large mass lesion mimicking a meningioma in the left parietal convexity. However, neither dural enhancement nor tail sign indicative of meningioma was observed. Angiography showed prominent feedings from branches of the internal carotid and basilar arteries rather than the external carotid artery. For this reason, presurgically, we suggested hemangiopericytoma or other specific meningiomas as a differential diagnoses. Surgery confirmed that the tumor had no attachment to the dura mater and was covered by the arachnoid membrane. The bottom of the tumor adhered tightly to brain tissue. The origin was considered to be the brain surface, pia mater or a part of the arachnoid membrane. Histopathologically, the tumor was diagnosed as a SFT with findings of "attemless pattern" and diffuse CD34 staining. The radiological and surgical findings of the present case indicated in the cerebral convexity as a unique site of origin of SFT.