Harlequin sign concomitant with Horner syndrome after anterior cervical discectomy: a case of intrusion into the cervical sympathetic system.

Harlequin syndrome is a rare autonomic disorder referring to the sudden development of flushing and sweating limited to one side of the face. Like Horner syndrome, associating miosis, ptosis, and anhidrosis, Harlequin syndrome is caused by disruption of the cervical sympathetic pathways. Authors of this report describe the case of a 55-year-old female who presented with both Harlequin sign and Horner syndrome immediately after anterior cervical discectomy (C6-7) with cage fusion and anterior spondylodesis. They discuss the pathophysiology underlying this striking phenomenon and the benign course of this condition. Familiarity with this unusual complication should be of particular interest for every specialist involved in cervical and thoracic surgery.