The term “fusiform aneurysm” often causes confusion because it is sometimes wrongly used synonymously with the term “dissecting aneurysm.”
We report a rare case of dissecting aneurysm in the left middle cerebral artery (MCA). A 45-year-old woman was admitted to our hospital with right hemiparesis on January 28, 1993. CT showed an infarct in the territory of the perforating branch of the M1 segment. Carotid angiogram showed a linear stenosis in the M1 distal portion. The patient was treated conservatively, and remained neurologically stable for 9 years following initial presentation, but serial magnetic resonance angiography (MRA) revealed growth of the aneurysm. Carotid angiogram showed a fusiform aneurysm of the M1-2 portion.
The patient underwent surgery by left pterional approach on November 11, 2002. The wall was yellow, firm, and arteriosclerotic. Finally, it was coated with Bemsheet soaked in Biobond. The postoperative course was uneventful.
We suggest that in the present case of fusiform aneurysm, the pathogenesis is dissection. Careful interpretation of serial angiograms and magnetic resonance images will be necessary for a long time because the disease may progress. If the aneurysmal size increases, surgery must be evaluated.