Concurrent Horner's and Harlequin syndromes.

Horner's syndrome and Harlequin syndrome are both caused by disruptions to the sympathetic supply to the face. They have a varied aetiology, including intraneural dysfunction, extra- or intraneural compression, and idiopathic as well as iatrogenic causes. Horner's syndrome can occur as a rare complication of thyroid surgery and the Harlequin sign has only been documented as a complication of cervical surgery in a handful of paediatric patients. We present a patient who developed both conditions subsequent to excision of a papillary carcinoma with a neck dissection. We illustrate the anatomical basis for this presentation and highlight the need for its appreciation. This is of particular interest as it impacts on several specialities operating in the cervical and thoracic fields.