[Clinical pseudo-peripheral presentation of cerebral lesions]

Small size cerebral lesions, located strategically, can determine the presence of sensitive and motor signs limited to a part of an extremity, clinically suggesting peripheral nervous system affectation, determining erroneous diagnostic and therapeutic decisions. We present 5 patients initially diagnosed of peripheral nervous system pathology, which were finally diagnosed of cerebral lesions (2 lacunar infarcts, multiple sclerosis, progressive multifocal leucoencephalopaty, multicentric astrocytoma). In all, clinical examination disclosed incongruous distribution of the sensitive manifestations and myotatic reflexes were present. CT studies were normal in three patients whereas MRI showed lesions in all cases. Lesions were smaller than 1.5 cm in diameter (greater in the case of multicentric astrocytoma), and were subcortically located in the opposite cerebral hemisphere to the affected extremity. Sensitivomotor signs restricted to an extremity not concordant with a nervous or radicular distribution and with presentation of myotatic reflexes, make it necessary to look for a central nervous system lesion. Lesion will be located in the opposite cerebral hemisphere and MRI will be the elective complementary exam.