Horner’s Syndrome and Mediastinal Schwannoma

Abstract

A 13-year-old boy developed right-sided Horner’s syndrome following resection of a benign mediastinal schwannoma extending from T1 to T3. Postoperatively, he exhibited ptosis, miosis, and anhidrosis, confirmed by starch iodine testing. The tumor likely involved the upper thoracic sympathetic ganglia—a rare site for schwannomas. This image highlights a rare iatrogenic cause of preganglionic Horner’s syndrome. While Horner’s is classically associated with apical lung or cervical lesions, this case emphasizes the importance of recognizing postoperative Horner’s syndrome as a clinical clue to cervicothoracic sympathetic injury. It highlights the value of anatomical-clinical correlation in localizing lesions along the sympathetic pathway.