Atypical MRI Findings in a Spinal Dural Arteriovenous Fistula - Histology as Clue to the Diagnosis (P05.258)

Abstract

Objective: Atypical presentations of spinal dural arteriovenous fistulas (SDAVF) represent a rare condition. Background In differential diagnostic reflections one should keep in mind atypical SDAVF as a significant cause of myelopathy. Design/Methods: We present an elucidating case of atypical diagnostic features in SDAVF. Results: A 60-year-old man developes a fluctuating spinal syndrome over a 3.5-year period. He presents with undulating spastic paraparesis, paresthesias in both legs, disturbances of micturition and defecation, sexual dysfunction and gait difficulties. Spinal MRI demonstrates a slightly contrast enhancing intramedullary lesion with an extension from D6 through D10. Due to the fluctuating clinical course, a SDAVF is considered, but the MRI shows no dilated veins or conus involvement. Cerebrospinal fluid findings are normal. With a differential diagnosis of either myelitis or spinal astrocytoma, treatment with corticosteroids and plasmapheresis is started without any effect. A spinal biopsy reveals no evidence of a tumor, but abnormal fibrotic blood vessels are seen. Therefore a spinal angiography is performed, which shows a SDAVF starting from the segmental thoracic medullary artery at D6 level and slowly draining into a not dilated vein, ranging over 5 vertebrae with no efflux out of the spinal canal. Since embolization seems too dangerous because of the connection between the involved segmental medullary artery and a posterior spinal artery, the fistula is disconnected surgically. During the operation, an atypical course of the vessels on the rather left side of the spinal cord is seen, explaining the atypical MR-findings. Postoperative MRI shows regression of medullary hyperintensity. Conclusions: In this case, the atypical findings in MRI without dilated veins or conus involvement lead to the misdiagnosis of a tumor. Only after the results of a spinal biopsy demonstrating pathological blood vessels spinal angiography is performed. With clinical symptoms of a SDAVF, a spinal angiography is justified even in MRI-negative presentations. Disclosure: Dr. Becker has nothing to disclose. Dr. Kraemer has nothing to disclose. Dr. Stracke has received personal compensation for activities with EV 3 as a consultant. Dr. Keyvani has nothing to disclose. Dr. Berlit has nothing to disclose.