A rare journey of a thymoma: A case report.

Introduction And Importance: Thymoma is the most common primary anterior mediastinal tumor in adults. Invasive thymomas infiltrate organs adjacent to the mediastinal pleura, including the lungs, great vessels, heart, pericardium, and diaphragm. Complete resection of invasive thymoma leads to a better prognosis.

Case Presentation: We report a case of protrusion of an invasive thymoma infiltrating the left upper lobe of the lung with intraluminal growth into the left brachiocephalic vein without direct invasion of the vessel wall. In this case, the thymic vein and the left brachiocephalic vein were thoroughly examined intraoperatively. A venotomy was performed to remove the tumor thrombus, and histopathological examination confirmed tumor protrusion via the thymic vein without direct invasion.

Clinical Discussion: Preoperative identification of tumor protrusion into the thymic vein is challenging therefore a thorough intraoperative examination of the thymic vein is essential to ensure the removal of the residual tumor in an invasive thymoma. Our finding points towards the possibility of the thymic vein being one of the potential pathways of tumor spread to the brachiocephalic vein.

Conclusion: A thorough examination of the thymic vein is essential to confirm and ensure the removal of the residual tumor. Complete resection of invasive thymoma with adjuvant chemotherapy leads to a better prognosis.