[A case of cerebellar arteriovenous malformation with hemifacial spasm at onset].

A case of cerebellar AVM onset with hemifacial spasm was reported. The patient, a 47 year old woman, had been suffering from lt. hemifacial spasm for 10 years, and she visited our hospital for operation. Preoperative angiography revealed that there was an AVM in the lt. cerebellar hemisphere fed by the lt. SCA and the lt. PICA. In addition, a non-ruptured saccular aneurysm was observed on the feeding SCA. The microvascular decompression was performed and the AVM was removed, since the lt. facial nerve had been compressed by this elongated and redundant PICA. After the operation, lt. hemifacial spasm disappeared. Two months after the operation, the aneurysm disappeared angiographically. These findings indicated that the hemodynamic stress due to the presence of AVM seemed to have resulted in ectasia or redundancy of the PICA and in the development of the aneurysm. Such a case was quite rare and it may be the first time to be reported in literatures.