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Int J Clin Exp Pathol 2013;6(7):1427-1431

Case Report
Retroperitoneal dedifferentiated liposarcoma with osteosarcomatous components: a
case report

Taishi Fujii, Takuma Arai, Masahiro Sakon, Shinji Sawano, Yoshitaka Momose, Keiko Ishii, Shiro Miwa

Department of Surgery, Okaya Municipal Hospital, Hon-machi 4-11-33, Okaya, 394-8512, Japan; Department of Pathology, Okaya Municipal
Hospital, Hon-machi 4-11-33, Okaya, 394-8512, Japan

Received May 13, 2013; Accepted June 3, 2013; Epub June 15, 2013; Published July 1, 2013

Abstract: We report a rare case of recurrent retroperitoneal dedifferentiated liposarcoma with osteosarcomatous components. An 82-year-old
male diagnosed with recurrent retroperitoneal liposarcoma underwent a tumor resection. Histologically, osseous matrix with osteoid and
mature hyaline cartilaginous tissues with high cellularity were observed in a fibrous background through most of the tumor, and scattered
MDM2- and CDK4-positive atypical hyperchromatic stromal cells were detected surrounding the dedifferentiated areas. Dedifferentiation occurs
in up to 10% of well-differentiated liposarcomas, frequently resembling a malignant fibrous histiocytoma-like pleomorphic sarcoma. In contrast,
divergent differentiation with osteosarcomatous components is considered to be extremely rare. (IJCEP1305015).

Keywords: Dedifferentiated liposarcoma, osteosarcoma, retroperitoneum

Address correspondence to: Dr. Takuma Arai, Department of Surgery, Okaya Municipal Hospital, Hon-machi 4-11-33, Okaya, 394-8512,
Japan. Phone: +81-266-23-8000; Fax: +81-266-23-0818; E-mail: t-arai@gd5.so-net.ne.jp