[Primary liposarcoma of the anterior mediastinum--case report and review of literature].

A 76-year-old male with anterior mediastinal tumor was admitted to our hospital. He had undergone mediastinal lipoma surgery 3 years earlier. The tumor was excised surgically. Microscopic sections of the tumor showed liposarcoma composed of myxoid tissue. Further examination of prior specimens taken from this patient proved this case to be a recurrence of liposarcoma. Poorly differentiated tumors, which pathologically tend to be more cellular with less fat per cell component, are likely to have high CT numbers. But CT number is not sufficient to distinguish well-differentiated liposarcoma from benign lipoma.