Upper thoracic intradural-extramedullary cavernous malformation presenting as subarachnoid hemorrhage without spinal dysfunction: a case report and review of the literature.

A 45-year-old man had subarachnoid hemorrhage (SAH) which was confirmed by lumbar puncture, since it was negative on head computed tomography. The result of neurological examination was normal. Following pan-cerebral angiography and cranial magnetic resonance imaging (MRI) failed to find out the cause of bleeding. The whole spinal MRI revealed an intradural-extramedullary mass lesion at the upper thoracic level which was consistent with cavernous malformation after surgery. When patients presented with SAH of no spinal symptoms, the diagnosis of an intradural-extramedullary cavernous malformation is challenging. A whole spinal workup should be considered in a patient with spontaneous SAH when bleeding from intracranial origin is carefully excluded.