Rare Spontaneous Disappearance of Intracranial Aneurysm.

An unruptured anterior circulation, nongiant saccular cerebral aneurysm (located at the clinoid segment [C3] of the internal carotid artery [ICA] and growing into the carotid cave) was detected at a medical checkup and diagnosed from subsequent examinations. The aneurysm was observed and followed up with radiologic examinations. An examination performed 12 years after diagnosis revealed the disappearance of the aneurysm. This observation should be kept in mind, that it is possible for an unruptured aneurysm to undergo spontaneous thrombosis without any intervention.