Horner syndrome associated with ipsilateral facial and extremity anhydrosis

We report a patient with Homer syndrome together with anhidrosis affecting the ipsilateral face and extremities confirmed with starch-iodine and sympathetic skin response testing. No anatomic lesion was apparent. This is the first reported case in which Homer syndrome has been associated with such extensive hemibody sympathetic dysfunction in the absence of other neurologic findings. We propose a developmental disorder of neural crest migration as the cause.