Coexisting harlequin and Horner syndromes after paediatric neck dissection: a case report and a review of the literature.

Harlequin syndrome, the presentation of hemifacial flushing and sweating, is a well recognized, though rarely reported, phenomenon associated with cervical sympathetic trauma. It is thought to result from disruption to sudomotor and vasomotor neurons present in the cervical sympathetic chain. The more common Horner's syndrome classically comprises the triad of unilateral miosis, ptosis and ipsilateral facial anhydrosis, and may also present as a sequela of cervical sympathetic denervation. We report a 26-month-old child with concomitant Horner's and harlequin syndromes, following neck dissection to address a large cervical lymphatic malformation. To our knowledge this is the first reported case of both syndromes resulting from surgery, and illustrates the particular challenge of lymphatic malformations in neck surgery due to their non-adherence to anatomical planes.