Postoperative Harlequin Syndrome: Case Report of a Rare but Clinically Striking Condition.

We present a case of a 2-year-old boy who underwent thoracoscopic resection of a left paraspinal mediastinal mass and developed Harlequin syndrome postoperatively. Harlequin syndrome is a rare neurological condition characterized by unilateral hyperhidrosis and erythema of the head and neck. Our discussion highlights this condition and other differential diagnoses that may present similarly in the postoperative period.