[A case of posterior cerebral artery territory infarction with micropsia as the chief complaint].

A 63-year-old man was admitted to the hospital complaining that all objects in his vision suddenly appeared small. Examination on admission revealed amnesia of recent events, recognition memory deficits, emotional disturbance, right upper quadrantanopsia and micropsia. The patient was diagnosed as posterior cerebral artery territory infarction based on brain CT scan and MRI findings which showed an ischemic lesion involving the left occipital lobe and hippocampus. We regarded the quadrantanopsia to have originated in the occipital lobe lesion and memory and emotional disturbances to have originated in the hippocampal lesion. After admission, micropsia and disturbances of memory and emotion improved within a month, but the quadrantanopsia did not recover. A comparison of the 25th and 2nd day brain CT scans indicated that the low density of the ischemic lesion near the hippocampus had become less clear and smaller. These findings suggest that the pathogenesis of micropsia in this case was a visual perceptional abnormality due to edematous change in the structures near the hippocampus. Cases of occipital artery territory infarction with micropsia, disturbances of memory and emotion, and quadrantanopsia appear to be rare, but micropsia may be overlooked since it is often masked by disturbance of memory or emotion.