Spinal arteriovenous fistula coexisting within a spinal lipoma: report of two cases

INTRODUCTION: Spinal lipoma and spinal arteriovenous fistula (sAVF) are different pathologies and their co-existence is extremely rare. Here we reported two cases of adult-onset sAVF occurring within a spinal lipoma and with review the literature in an attempt to identify the mechanisim of and optimal treatment of this condition. CASE PRESENTATION: Case 1 was a 51-year-old man who was treated by embolization of the feeding artery and ligation of the draining vein. Case 2 was a 53-year-old man who was treated by embolization and resection of the tumor containing the shunt zone. In both cases, symptoms improved after surgery. However, in Case 1, angiography at 1 month after the surgery revealed recurrence of the arteriovenous shunt. DISCUSSION: A literature search revealed only nine other similar case reports. All cases, including ours occurred in adults. In almost all cases, the shunt was located within the spinal lipoma. Pathologic examination revealed venous hypertension, but no evidence of congenital vascular malformation. Given that lipomas release angiogenic factors, the presence of a spinal lipoma may indicate its involvement in the development of acquired sAVF. Our two cases might represent a new subtype of sAVF. Based on our experiences, we recommend resection of the tumor containing the shunt for the management of sAVF.