A rare mediastinal-type superior vena cava cavernous hemangioma successfully treated with surgical resection under cardiopulmonary bypass condition: a case report.

Of the anterior mediastinal tumors, cavernous hemangiomas originating from the superior vena cava (SVC) in this region are rare. We present a case in which the chest CT scan during a health check-up revealed an irregular, patchy soft-tissue density shadow in the thymic region, measuring approximately 5.5 × 3.5 cm in diameter. Eight months later, an enhanced chest CT scan at our hospital demonstrated an irregular, mass-like soft-tissue density shadow in the anterior mediastinum, with poorly defined borders adjacent to vascular structures and an increased diameter of approximately 6.0 × 3.8 cm. During surgery, the lesion exhibited a hemangioma-like appearance, with its base located at the confluence of the left and right innominate veins into the SVC. Mediastinal lesion resection and SVC plasty were therefore performed under cardiopulmonary bypass. Postoperative pathological examination confirmed the diagnosis of SVC cavernous hemangioma. The patient recovered uneventfully and was discharged on postoperative day 6. A follow-up chest CT scan more than three months after surgery showed imaging changes consistent with resection of the cavernous hemangioma. In addition, atelectasis in the right middle and lower lobes had significantly improved compared to earlier imaging. This case offers valuable clinical experience and insights to support treatment decision-making in similar scenarios.