Dedifferentiated Liposarcoma in the Retroperitoneum in an Atomic Bomb Survivor: Report of a Case

A 76-year-old Japanese man was admitted to Kosei-Nenkin Hospital (Osaka, Japan) in November 2006; his chief complaint was a 10-kg loss in body weight over 3 months prior to admission. Abdominal computed tomography (CT) and dynamic magnetic resonance imaging (MRI) showed three masses in the retroperitoneum. The patient subsequently underwent surgery. The final histopathological diagnosis of tumors 1 and 2 was malignant fibrous histiocytoma of the retroperitoneum, and tumor 3 was a well-differentiated liposarcoma. By the presence of the liposarcoma, tumor 1 and 2 were thought to be the dedifferentiated areas of liposarcomas. At the age of 16, the patient had been exposed to radiation from the atomic bomb at Hiroshima towards the end of the Second World War. We postulate that in this case, radiation from the atomic bomb may have played an important role in the development of the sarcomas.