A case of dedifferentiated liposarcoma in retroperitoneum.

Dedifferentiated liposarcoma occurs in less than 10% of all liposarcomas and is found most often in the retroperitoneum and extremities. Although cases of the primary dedifferentiated liposarcoma have been sporadically reported internationally, only one case with cm size originated from spermatic cord and one case with cm size in right gluteal region have been reported in Korea, but not in retroperitoneum. We report one case of the primary giant dedifferentiated liposarcoma occurred in retroperitoneum with cm size and 4,250 g weight. A 56-year old man was admitted due to the weight loss and diffuse abdominal pain. The abdominal computed tomography showed that a round huge mass was pressing the surrounding structures and showed delayed enhancement. Surgical excision was carried out. Histologically the tumor was composed of well differentiated liposarcomatous area and malignant fibrous histiocytoma-like dedifferentiated area. The patient refused further treatment and now he is undergoing he follow-up.