[A case of left hemi-facial metamorphopsia induced by infarction of the right side of the splenium of the corpus callosum].

We describe a patient, 61-year-old left-handed Japanese woman, who presented with left hemi-facial metamorphopsia after infarct that extended from the splenium of the corpus callosum to the major forceps on the right side. Past medical history revealed a right putaminal hemorrhage with amnesic aphasia. She complained that the right side of people's faces, that is, the left side when visualized by her, seemed distorted. When she looked at other people's faces, the right half of the faces looked smaller than the left half, and the eyes, noses, and mouths appeared to be hanging toward the center of their faces. This phenomenon was observed for whomever she visualized. She stated that objects other than the face looked normal. Her visual acuity and visual field were normal. Callosal disconnection syndrome was not presented. Magnetic resonance imaging of the brain on diffusion weighted image revealed a high intensity area that extended from the splenium of the corpus callosum to the major forceps on the right side. Electroencephalography did not show any epileptic discharge. Her visual symptoms improved gradually. The mechanism of hemi-facial metamorphopsia remains obscure. We hypothesized that this patient developed left hemi-facial metamorphopsia because of the disrupted transfer of visual information of the left side of face at the splenium of the corpus callosum and the major forceps, which may be the responsible lesion of hemi-facial metamorphopsia.