Conus medullary arteriovenous malformation mimicking intramedullary tumor: a case report

Background Vascular malformation of the spine accounted for 3–4% of all intradural lesions. Spinal arteriovenous malformation (AVM) is often missed because of overlapping symptoms with other pathology and ambiguous imaging. Here, we report a conus medullary AVM that mimics intramedullary tumours either from clinical findings or MR imaging. Case presentation We report a 24-year-old man with left foot monoparesis, paresthesia, and intermittent claudication for the last 3 months. Magnetic resonance imaging revealed a strongly enhanced intramedullary lesion with a hypointense signal on T1-weighted images and a hyperintense signal on T2-weighted images without flow void, suggesting an intramedullary tumour of ependymoma. Left-sided hemilaminectomy was performed, revealing an AVM on conus medullary. Microsurgical resection was performed by subsequently ligating the arterial feeder and draining vein using a temporary clip. Improvement of neurological status without postoperative sequelae was noted. Conclusions Because of the similarity in epidemiology, symptoms, clinical progression, and imaging, suspicion of spinal AVM should remain. This case highlights that appropriate and meticulous surgical resection can preserve the patient's neurological function.