Building an Endovascular Skeleton: Prophylactic Stenting in a Hybrid Approach to a Thymic Carcinoma with Supra-aortic Trunk Encasement.

INTRODUCTION: Locally advanced thymic carcinomas with supra-aortic vessel involvement pose significant surgical challenges and are historically often deemed unresectable. Neoadjuvant radiotherapy further complicates surgical resection by inducing severe tissue fibrosis. The integration of endovascular techniques with open surgery can expand the boundaries of oncological radicality; however, literature on such hybrid approaches for mediastinal tumours remains limited. REPORT: A 45 year old man presented with a 6 × 9 cm locally advanced thymic squamous cell carcinoma causing tracheal compression. The mass entirely encased the left common carotid artery (LCCA) and partially encased the innominate and left subclavian arteries. Following a partial response to neoadjuvant chemoradiotherapy, a staged multidisciplinary surgical approach was planned. To mitigate the risk of catastrophic vascular injury during dissection of irradiated tissues, prophylactic stent grafts were first deployed in the innominate and left subclavian arteries via right axillary access under local anaesthesia. Radical tumour resection was performed via a combined median sternotomy and cervical approach three days later. The pre-placed stents acted as a rigid "endovascular skeleton", allowing safe and aggressive sub-adventitial tumour dissection. The LCCA was resected en bloc with the tumour, and vascular continuity was restored using a left subclavian to carotid prosthetic bypass. The patient recovered well and was discharged on post-operative day 19. At the three month follow up, he was asymptomatic, with imaging confirming the patency of both the stents and the bypass. CONCLUSION: Prophylactic endovascular stenting of partially encased supra-aortic vessels offers crucial structural and haemostatic protection, facilitating safe and aggressive oncological resection in hostile, irradiated fields. This tailored, hybrid multidisciplinary approach provides a viable pathway to achieving true oncological radicality (R0) in highly complex mediastinal tumours previously considered inoperable.