Cheiro-oral syndrome: identification of the lesion sites and a proposal for its clinical classification

Five cases suffering from unilateral paresthesia over the corner of the mouth and the hand on the same side were examination for cheiro-oral syndrome. Of these, three cases were typical and the other were variant cases associate with transient hemi-signs. Lesion sites were identified by computed tomographic (CT) scan, magnetic resonance imaging (MRI) or both. Of the five patients, lesions were due to thalamic infarction in three cases, pontine hemorrhage in one case, and tumor compression on the right frontoparietal lobe in the last case. The pathophysiology of all cases were classified according to location of the lesion on the thalamus, the pons, and the parietal lobe, which are the usual anatomical sites responsible for this syndrome. Based on the three typical cases and thirteen cases cited from the English literature, a clinical classification has been established. The classification is based on age at the time of onset, gender, lesion site, etiology, risk factors, and certain clinical features. These sixteen cases fell into three distinct groups: a) those in which the thalamic lesions were related to infarction, b) those in which tumors, or in rare cases infarction, were found in the parietal lobe, and c) those in which hemorrhage occurred in the pons. Using this classification, the cheiro-oral syndrome can be more systematically defined.