Limbic encephalitis presenting with topographical disorientation and amnesia.

A case of paraneoplastic limbic encephalitis presenting with topographical disorientation is reported. A 70 year old woman became unable to identify familiar buildings and landscapes and could not recall the way to destinations she had known very well for years. She also showed attentional disturbance and severe anterograde amnesia. Her retrograde amnesia extended for one year at most. No other neuropsychological deficits were noted. Thus her topographical disorientation was of the primary form. Specific tests related to topographical disorientation showed that her two main symptoms seem to fall into the categories of landscape agnosia and heading disorientation. T2 weighted magnetic resonance imaging revealed high intensity signals in the anteromedial temporal lobes bilaterally, in the right posterior parahippocampal gyrus, in the right retrosplenial region, and in the right inferior precuneus. Anti-Hu antibody was found in the serum. This case shows that topographical disorientation can be a primary symptom of limbic encephalitis.