Lipoma on the corpus callosum in a patient with schizophrenia-like episode: is there a causal relationship?

Disturbed interhemispheric communication has been proposed as responsible for schizophrenia. We present a case of a schizophrenia-like episode with no neurologic or other psychiatric symptoms. However, magnetic resonance imaging revealed a lipoma on the splenium of the corpus callosum. Neuropsychologic examination revealed normal interhemispheric transfer, but a slight dysfunction associated with right-hemispheric anterior regions. Rather than supporting the hypothesis of a causal relationship between callosal abnormality and schizophrenia-like symptoms, our findings argue against a direct causal relationship between lesion site and psychotic episode. We conclude that cerebral abnormality per se may represent a risk factor for neuropsychiatric symptoms.