Atypical lipomatous tumors in the anterior mediastinum indicating multicentric development-A case report

A 62-year-old man experiencing anterior chest pain was hospitalized at our institution. Computed tomography and magnetic resonance imaging showed an 85×44-mm tumor pressing against the left side of the heart in the left anterior mediastinum; the tumor showed a homogeneous fat density. The tumor, covered by a capsule, was completely removed with sufficient surrounding adipose tissue by video-assisted thoracic surgery (VATS). We diagnosed it as an atypical lipomatous tumor (well-differentiated liposarcoma). The patient was discharged and followed-up as an outpatient. Six months later, a new tumor in the right anterior mediastinum with features similar to those of the previous tumor was noted. The second tumor was successfully removed by VATS. This tumor was also diagnosed as an atypical lipomatous tumor with its own capsule, and was not connected to the left anterior mediastinum. Therefore, bilateral early multicentric development was indicated.