title: Retroperitoneal well-differentiated inflammatory liposarcoma: a diagnostic dilemma.
abstract: We present a case of retroperitoneal well-differentiated inflammatory liposarcoma that was extremely difficult to diagnose preoperatively. Computed tomography and magnetic resonance images showed a 5-cm homogeneous soft-tissue mass with a decreased apparent diffusion coefficient and without fat component in the retroperitoneum. Minimal fat stranding was detected around the mass. The preoperative working diagnosis was malignant lymphoma or inflammatory pseudotumor, whereas the final diagnosis after surgery was well-differentiated inflammatory liposarcoma. As a result, only a large component of lymphoid infiltration was recognized as a tumor preoperatively, and minimal fat stranding represented a component of lipoma-like liposarcoma. In this entity, a lipomatous component could easily be missed on radiologic imaging because of the conspicuity of lymphoid infiltration. We should consider the possibility of this variant when we evaluate a retroperitoneal tumor.
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Rinsaku
authors.initials: R
authors.lastname: Kawano
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nishie
authors.forename: Kengo
authors.initials: K
authors.lastname: Yoshimitsu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Irie
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tajima
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hirakawa
authors.forename: Kousei
authors.initials: K
authors.lastname: Ishigami
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ushijima
authors.forename: Daisuke
authors.initials: D
authors.lastname: Okamoto
authors.forename: Hidetake
authors.initials: H
authors.lastname: Yabuuchi
authors.forename: Akinobu
authors.initials: A
authors.lastname: Taketomi
authors.forename: Yunosuke
authors.initials: Y
authors.lastname: Nishihara
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Fujita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda