Desmoid tumor arising from omohyoid muscle: The first report for unusual complication after transaxillary robotic thyroidectomy.

BACKGROUND Transaxillary robotic (TAR) thyroidectomy has been performed for better aesthetic results by many surgeons. In this report, we describe a rare case of a desmoid tumor developed after TAR thyroidectomy, which is speculated to be a late-term complication. METHODS AND RESULTS A 61-year-old woman with a history of papillary microcarcinoma had experienced a large left neck mass that had grown over 2 years. The patient underwent TAR thyroidectomy (right lobectomy and isthmectomy) via the right axilla almost 2.5 years previously. Physical examination revealed a 6-cm, firm mass fixed to the left anterior neck. The mass was fixed to the omohyoid muscle. The 5.9- × 4.7- × 4.5-cm tumor with the surrounding muscles was excised in an en bloc fashion. Pathologic examination confirmed the diagnosis of a desmoid tumor. CONCLUSION This case suggests that desmoid tumors could develop late after TAR thyroidectomy. Thus, careful observation of the surgical wound may be necessary after TAR thyroidectomy.