A case of the corpus callosum and alien hand syndrome from a discrete paracallosal lesion

Here we present a patient with an isolated paracallosal brain lesion who exhibited behavioral changes associated with the corpus callosum syndrome (CCS) including features of the alien hand syndrome (AHS). The CCS is also known as the split-brain syndrome, the syndrome of hemisphere disconnection, the syndrome of brain bisection and the syndrome of the cerebral commissures. Because most reported cases of CCS were caused by tumors which extended beyond the corpus callosum (CC) and did not always induce a complete disconnection, there was much controversy about the role of the CC and the existence of a specific CCS. Aside from surgically based cases, the full complement of the CCS is infrequently clinically encountered. The patient described has a classic CCS from natural causes. This case report is unique in exhibiting a complete CCS with AHS secondary to an ischemic event affecting the left pericallosal region. To our knowledge this is the first case report of such a combination.