[A case of topographic disorientation without right occipital lesion]

A 73-year-old right-handed man developed topographical disorientation, left homonymous hemiianopsia, left visuospatial neglect and mild visual memory disturbance following the right hemispheric infarction. The visual agnosia is very similar to agnosia for streets because he could not identify familiar buildings and streets even though he could remember their way. He did not have prosopagnosia. His brain MRI demonstrated infarction at the right anterior choroidal artery area, including right thalamus, caudate tail and optic radiation. SPECT showed the mild decrease of rCBF at the right temporoparietal cortex. His topographic disorientation faded and finally disappeared about 3 weeks after its onset. Our case is atypical because of sparing the posterior part of the right parahippocampal gyrus where plays an important role in the development of agnosia for streets.