Follicular dendritic cell sarcoma is a rare, low-grade cancer derived from follicular dendritic cells, which serve as accessory cells to the lymphoid system. Here, we describe the case of a 57-year-old man who had a mediastinal mass with aortic involvement incidentally identified during evaluation for indeterminate pulmonary nodules. The mass, later diagnosed as follicular dendritic cell sarcoma, was successfully treated with surgical resection aided by the placement of an endovascular aortic stent graft.