[A case of postcentral infarction presenting discriminative sensory impairment limited to the distal leg on one side].

Presented is a case of postcentral infarction in a 70-year-old woman, which manifested as sensory disorders localized at the distal portion of the right lower extremity. Sensory disorders were characterized by the disturbances of discriminative sensation. Elemental senses were nearly normal. MRI revealed cerebral infarction localized at the superior portion of the postcentral gyrus and medial surface of the parietal lobe and the paracentral lobule of the left cerebral hemisphere. Carotid echography demonstrated stenotic lesions of the bilateral internal carotid arteries, suggesting that infarction of the cortical branch of the anterior cerebral artery due to artery-to-artery embolism was the cause of the condition. Cortical sensory disturbances due to lesions at the somatosensory area of the postcentral gyrus often appear on the upper extremities and face, and rarely occur as sensory disturbances that were localized in the distal portion of the lower extremities, as in this patient. The case suggests that it is important to keep in mind that sensory disorders that are localized in a single extremity with a distribution that suggests peripheral nerve lesions can be caused by cerebral cortical lesions.