Sacral lipoma of the filum terminale with dural arteriovenous fistula. Case report.

A patient presenting with progressive paraparesis was found to have a dural sacral arteriovenous (AV) fistula. His condition deteriorated abruptly after thoracolumbar angiography. Embolization of the fistula improved the patient's status so that he was able to walk with crutches. One year later his neurological condition worsened. He was treated via an enlarged laminectomy because of uncertainty concerning a lipoma noted on the initial computerized tomography scan. The lesion consisted of an intradural filum terminale lipoma associated with an AV fistula, both of which were excised. The patient's condition was unchanged 6 months later. The different types of spinal lipomas and spinal AV malformations are reviewed, and mechanisms are proposed to explain the clinical deterioration in this patient. Venous hypertension seems to be the most likely possibility. The lipoma may have produced local hypervascularization of the dura mater with a subsequently acquired AV fistula.