Intradural spinal cord tumor presenting as a subarachnoid hemorrhage: magnetic resonance imaging diagnosis. Negative findings on four-vessel angiography after a subarachnoid hemorrhage are seen in 5 to 30% of patients. A previously silent lesion in the spinal canal may be responsible for the ictus in a small percentage of this group. The etiological factors include tumors and arteriovenous malformations; however, investigations of such lesions have been limited to patients with signs and symptoms of spinal cord or nerve root pathological processes. This report describes the management of a 56-year-old woman with clinical findings typical of an aneurysmal subarachnoid hemorrhage and negative findings on cerebral angiography, in whom magnetic resonance imaging with gadolinium enhancement revealed an intradural extramedullary cervical schwannoma. For this reason, cervicothoracic magnetic resonance imaging with gadolinium enhancement should be considered as an adjunctive scanning examination in all patients with a subarachnoid hemorrhage and negative findings on angiography. 