title: Dedifferentiated liposarcoma of the retroperitoneum with osteosarcomatous component: report of two cases.
abstract: We describe two cases of ossified soft tissue tumors of the retroperitoneum. Computed tomographic and magnetic resonance imaging both revealed retroperitoneal masses consisting of two components -- densely ossified and lipid-rich components. In one case, a 50-year-old man, a histological diagnosis of dedifferentiated liposarcoma with osteosarcoma was made based on the needle biopsy of the two components. In another case, a 54-year-old man, surgical resection of the complex perirenal mass was performed and the same diagnosis was made. Although an ossified component represent high-grade lesion, the fatty component is an important clue to the diagnosis of dedifferentiated liposarcoma. The imaging features may be similar to those of malignant mesenchymoma, which is not a currently used term.
authors.affiliation: Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Toshiyasu
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ehara
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Jun
authors.initials: J
authors.lastname: Nishida
authors.forename: Hideo
authors.initials: H
authors.lastname: Shiraishi
mesh_terms: D006801:Humans; D008080:Liposarcoma / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000000981:diagnostic imaging*; D012516:Osteosarcoma / Q000000981:diagnostic imaging*; D012186:Retroperitoneal Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*