Horner's Syndrome as a Rare Complication of Thyroidectomy With Central Neck Dissection: A Case Report and Review of Potential Mechanisms.

Horner's syndrome (HS) is characterized by miosis, ptosis, enophthalmos, anhidrosis, and vascular dilation on one side of the face, resulting from an interruption in the oculosympathetic pathway. Here, we present a 55-year-old female patient diagnosed with thyroid carcinoma metastasis via fine-needle aspiration biopsy of the right supraclavicular lymph node. She underwent total thyroidectomy and right central lymph node dissection. On the first postoperative day, the patient developed right-sided miosis and upper eyelid ptosis, leading to a diagnosis of HS. Although this rare complication following thyroid surgery has been reported, its exact mechanism remains unclear. We attribute this occurrence to cervical sympathetic chain injury during aggressive central dissection.