Spontaneous total thrombosis of distal superior cerebellar artery aneurysm.

We report the case of an aneurysm of the distal segment of the superior cerebellar artery (SCA) which showed complete spontaneous thrombosis. Initial angiography performed in another institution showed 3 non-ruptured aneurysms located on the right distal SCA, C3 segment of the right internal carotid artery (ICA) and left basilar artery (BA)-SCA bifurcation. The patient had two episodes of transient cerebellar ataxia of the right hand before admission to our hospital, but no neurological signs were noted on admission. Computed tomography (CT) and magnetic resonance image (MRI) showed a thrombosed mass on the right cerebellar peduncle, and angiography showed no filling of the right SCA from its origin. A follow up angiogram 9 month after endovascular surgery for other aneurysms showed no recanalization of SCA or the aneurysms. There are no previous reports of total spontaneously thrombosed non-giant aneurysms of the distal segment of the SCA.