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[Arteriovenous aneurysm of the corpus callosum with normal arteriography 9 years earlier].

Some arteriovenous malformations (A.V.M.s) visualized on a first angiography tend to enlarge gradually with time. Others A.V.M.s may decrease in size and even disappear. The authors report the case of a 18 year old woman admitted for a subarachnoid hemorrhage. A complete cerebral angiography was normal. Nine years later, an arteriovenous malformation of the corpus callosum was discovered. The reasons why angiography may fail to demonstrate an A.V.M., and the theories concerning the enlargement of A.V.M.S., are discussed.