Three cases of adult patients with subacute courses of progressive caudal spinal cord disease are presented. Computed tomography, magnetic resonance imaging, and myelographic studies were interpreted preoperatively as representing a spinal cord neoplasm in each case. No evidence of enlarged or abnormal surface vessels was observed by neuroimaging or intraoperatively. Biopsy specimens from each spinal cord lesion showed the typical histopathological features of a spinal vascular malformation. We conclude that vascular malformations of the caudal spinal cord can appear as isolated intramedullary lesions with apparently normal surface vessels and that these lesions may be difficult to distinguish from spinal cord neoplasms.