Retroperitoneal Liposarcoma With Leiomyosarcomatous Differentiation |
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Authors: | Masaki Suzuki Minoru Fukuchi Shinji Sakurai Hiroshi Naitoh Shinsuke Kiriyama Takaharu Fukasawa Yuichi Tabe Hayato Yamauchi Tomonori Yoshida Hiroyuki Kuwano |
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Institution: | 1.Department of Surgery, Social Insurance Gunma Chuo General Hospital, Gunma, Japan ;2.Department of Diagnostic Pathology, Social Insurance Gunma Chuo General Hospital, Gunma, Japan ;3.Department of General Surgical Science, Gunma University Graduate School of Medicine, Mebashi, Japan |
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Abstract: | We herein describe a 60-year-old Japanese man with a giant retroperitoneal liposarcoma undergoing leiomyosarcomatous differentiation. He was admitted to our hospital because of a 5-month history of dysphagia and abdominal distention. Abdominal computed tomography showed a giant tumor that occupied the entire retroperitoneal space. The majority of the mass was lipomatous and low density; both a heterogenous and solid mass were also present. A giant retroperitoneal liposarcoma was diagnosed, and tumor resection was performed. At surgery, the tumor was mostly isolated from the retroperitoneum and other organs. Histopathologically, the tumor comprised well-differentiated and dedifferentiated liposarcoma with heterologous differentiation of the leiomyosarcomatous components, which is a rare phenomenon in liposarcoma. The patient was alive 3 years after the first treatment, although he has had 3 local recurrences (approximately one recurrence yearly) and has been treated by repeated resection and radiotherapy.Key words: Retroperitoneum, Liposarcoma, Leiomyosarcomatous differentiationDedifferentiated liposarcoma (DL) is one of the most frequent sarcomas of the retroperitoneum. It is defined by the association of an atypical lipomatous tumor, namely, areas of well-differentiated liposarcoma (WDL), with a dedifferentiated component. WDL is composed of mature adipocytes and atypical stromal cells with an enlarged, hyperchromatic nucleus. Usually, the dedifferentiated part of the liposarcoma is composed of either a spindle/pleomorphic high-grade sarcoma or a mixoid/spindle cell low-grade sarcoma. The WDL component may be easily overlooked, and DL may thus be mistaken for another high-grade sarcoma. It has been reported in one study that approximately 5% of the dedifferentiated component showed heterologous differentiation, such as leiomyosarcoma, rhabdomyosarcoma, osteosarcoma, and angiosarcoma.1 A less common phenomenon is the occurrence of WDL with leiomyosarcomatous (LMS) differentiation.2 Limited to the retroperitoneum, only 8 cases of liposarcoma with LMS components have been reported.3–7 We herein report a case of retroperitoneal liposarcoma comprising WDL and DL, with LMS components, treated by surgical resection. |
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