Arteriovenous malformation of the filum terminale: an exceptional case.

Arteriovenous malformations (AVMs) of the spine display a variety of different locations, angioarchitectures, and clinical presentations. The authors describe an exceptional case of a filum terminale AVM that is not described in any classification and discuss the origin and management of this malformation. A 59-year-old woman was admitted in June 2012 for cauda equina syndrome. Magnetic resonance imaging and spinal angiography revealed an AVM of the filum terminale, located below the conus medullaris, fed by the anterior spinal artery. After an unsuccessful attempt to reach the nidus with a microcatheter, the AVM was resected. At 20 months after surgery, the patient was fully independent and radiological images confirmed the exclusion of the malformation. AVMs that originate from the filum terminale are exceptional. According to updated classifications, AVMs of the filum terminale should be categorized as a separate entity.