[A case of cerebellar hemispheric venous malformation presenting crossed cerebello-cerebral diaschisis].

A 49-year-old man was admitted to our hospital complaining of clumsiness in his left arm and leg that had 2 months' history with subacute onset. On examination he showed left sided ataxia but no other neurological deficits. A linear lesion was demonstrated in the left cerebellar hemisphere by X-ray computed tomography and magnetic resonance imaging without apparent hemorrhage and mass effect. Digital subtraction angiography revealed a venous malformation in the left cerebellar hemisphere but carotid arteries were normal. Relative distribution of cerebral blood flow was measured using single-photon-emission-computed tomography with rotating gamma camera and 123I-IMP. Reduced uptake was observed in the right frontal lobe (-15- -30%). However, the asymmetry disappeared 8 months later. The decreased blood flow in the contralateral cerebral cortex may be due to destruction of cerebello-thalamo-cortical pathways.