A Patient with an Anterior Condylar Confluence Dural Arteriovenous Fistula in Whom Reflux to the Anterior Medullary Vein Was Observed during Follow-Up.

Objective: We report a case of anterior condylar confluence dural arteriovenous fistula (ACC dAVF) in whom venous reflux presentation was converted to the anterior medullary vein (AMV) during the observation period. Case Presentation: A 63-year-old woman with ACC dAVF, which only had anterograde drainage routes, exhibited dizziness during the observation period. Magnetic resonance imaging (MRI) revealed an abnormal hyper-intense area in the pons to the medulla. We performed cerebral angiography and reflux to the AMV was found. As the other drainage route using the internal jugular vein (IJV) remained, transvenous embolization (TVE) was performed to treat this ACC dAVF. No neurological deficits were observed and hyper-intensity in the brain stem disappeared after treatment. Conclusion: Although such cases are markedly rare, it is necessary to keep in mind that ACC dAVF may convert to the venous reflux presentation to the AMV during the natural course.

Clear cell ependymoma of the fourth ventricle.

Two cases of clear cell ependymoma (CCE) of the fourth ventricle are reported in a 49-year-old woman with dysphagia and a 59-year-old woman with dizziness and gait disturbance. CCE is a relatively new variant of ependymoma added to the WHO classification of tumors in 1993. Tumor cells display an oligodendroglioma-like appearance with a clear perinuclear halo. Most infratentorial CCE tumors are located in the cerebellum. There are only three cases, including the present two cases, that have been reported to affect the fourth ventricle.