[Growing aneurysm presenting with Weber's syndrome and obstructive hydrocephalus--a case report].

A case with two cerebral aneurysms, in which one at the origin of the left superior cerebellar artery (SCA) grew and presented with Weber's syndrome and obstructive hydrocephalus, is reported. The patient was a 69-year-old female, who had severe headache and vomited. On admission, neck stiffness was recognized. CT scan showed findings of subarachnoid hemorrhage. Angiograms demonstrated two saccular aneurysms at the right middle cerebral artery (MCA) bifurcation and at the origin of the left SCA. Craniotomy and neck clipping of the aneurysm at the right MCA was performed. After discharge, left oculomotor palsy appeared and gradually progressed. Severe headache and right hemiparesis suddenly occurred two years after the first attack. On the second admission, CT scan revealed high density on the brain surface and a well enhanced round lesion at the left ambient cistern. Left vertebral angiogram demonstrated increase in size of the aneurysm at the left SCA. The patient was discharged after conservative therapy. Drowsiness and urinary incontinence appeared, and she was admitted for the third time three years after the first admission. CT scan showed an enhancing mass lesion sized 25 X 30 mm beside the left midbrain and obstructive hydrocephalus. The aneurysm at the SCA no longer seen on the left vertebral angiogram. V-P shunt was performed. Both Weber's syndrome and obstructive hydrocephalus in this case indicate an aneurysmal natural history, in which aneurysm becomes gigantic and thrombosed spontaneously.