Pial arteriovenous fistulas: dilemmas in prenatal diagnosis, counseling and postnatal treatment. Report of three cases.

We report three cases of the antenatal appearance of a pial arteriovenous fistula (AVF). In Case 1, the diagnosis of pial AVF was made by ultrasound examination at 32 + 3 weeks of gestation and confirmed by magnetic resonance imaging (MRI) at 34 + 3 weeks of gestation. After birth, the neonate had cardiac insufficiency and an embolization was performed 8 days postpartum which was followed by extended cerebral ischemia and death. In Cases 2 and 3 pial fistulae were diagnosed at birth. In Case 2, the patient was referred following the diagnosis of an aneurysmal malformation of the vein of Galen at 38 weeks of gestation. Owing to immediate delivery following her transfer, no ultrasound examination was performed and the diagnosis of pial AVF was established on the first postnatal day. An embolization was performed and the child is doing well. Case 3 presented with cardiomegaly at 30 weeks of gestation and cerebral ischemic lesions after birth. These cases highlight the difficulties encountered in the prenatal diagnosis of pial AVFs. The diagnosis should be considered in cases of unexplained cardiomegaly and it is also important to make sure that AVFs draining into the vein of Galen are not misdiagnosed as aneurysmal malformations of this vein. The complications of pial AVFs are cardiac failure and cerebral ischemia. Embolization is the treatment of choice; however it is a risky procedure in neonates.