Sacral Extradural Angiolipoma Associated with Tight Filum Terminale and Spina Bifida Coexisting with Spinal Arteriovenous Fistula

Abstract

Spinal arteriovenous fistula (AVF) may rarely associate with spinal dysraphism, that is, tethered spinal cord and spinal intradural lipoma. Spinal extradural angiolipoma coexisting with spinal AVF has not been reported in the literature. We reported an extremely rare case of sacral angiolipoma associated with tight filum terminale and sacral spina bifida coexisting with spinal AVF within this tumor. A 55-year-old women presented with progressive myelopathy for 10 months. She had a painless, slow-growing mass at her left buttock since birth. Magnetic resonance imaging of the lumbosacral spine showed an extradural mass at the level of S3-S4, extending from the spinal canal through the spina bifida to the subcutaneous fat of the left buttock. There was a low conus medullaris at S2. Magnetic resonance imaging of the thoracic spine disclosed venous congestion with tortuous intradural flow voids along both ventral and dorsal surfaces of the spinal cord. Magnetic resonance angiography and spinal angiography revealed a hypervascular mass at the sacral level and associated arteriovenous shunt with cranial drainage into an enlarged medullary vein. Due to an infected pressure sore on the mass, endovascular treatment was initially performed with minimal recovery. Six months after complete healing of her infected pressure ulcer, the patient underwent surgical removal of extradural mass containing the AVF, and subsequent release of the tight filum. Histologic findings were consistent with angiolipoma. Sacral extradural angiolipoma in the present case may be congenital in origin with development of an acquired spinal AVF within the tumor.