Breast Imaging: ORIGINAL ARTICLEPrimary Dedifferentiated Liposarcoma of the Retroperitoneum: Prognostic Significance of Computed Tomography and Magnetic Resonance Imaging FeaturesTateishi, Ukihide MD, PhD; Hasegawa, Tadashi MD, PhD; Beppu, Yasuo MD; Satake, Mitsuo MD; Moriyama, Noriyuki MD, PhDAuthor Information From the Divisions of Diagnostic Radiology (Drs Tateishi, Satake, and Moriyama), Pathology (Dr Hasegawa), and Orthopedics (Dr Beppu), National Cancer Center Hospital and Research Institute, Tokyo, Japan. This work was carried out by the Program for Promotion of Fundamental Studies in Health Sciences of the Organization for Pharmaceutical Safety and Research (Japan) and was supported in part by a Grant-in-Aid for Cancer Research from the Ministry of Health, Labor and Welfare (Japan). Reprints: Ukihide Tateishi, MD, PhD, Division of Diagnostic Radiology, National Cancer Center Hospital, 5-1-1, Tsukiji, Chuo-Ku, Tokyo 104-0045, Japan (e-mail: email@example.com). Journal of Computer Assisted Tomography: September-October 2003 - Volume 27 - Issue 5 - p 799-804 Buy Abstract Objectives To describe computed tomography (CT) and magnetic resonance (MR) imaging findings and to determine the prognostic significance of radiologic appearances in primary dedifferentiated liposarcoma of the retroperitoneum. Methods Initial CT and MR imaging studies of 20 pathologically confirmed cases of primary dedifferentiated liposarcoma of the retroperitoneum were retrospectively reviewed and assessed for correlations with the histopathologic features. CT and MR images were evaluated by 2 radiologists with agreement by consensus, and univariate analyses were conducted to evaluate survival with a mean clinical follow-up duration of 47 months (range, 5–114 months). Results Tumor invasion was more frequent in the anterior or posterior pararenal originating tumors than in pararenal tumors (P < 0.05). Well-defined nonlipomatous masses juxtaposed with fatty tumors were identified in all cases. Calcification or ossification was seen in 6 patients (30%) on unenhanced CT. Imaging findings including attenuation, signal characteristics, and enhancement patterns of nonlipomatous masses were nonspecific regardless of histologic variances. Recurrent tumors (n = 6) tended to invade surrounding organs. Univariate analysis revealed that calcification or ossification (P < 0.05) and first recurrence with duration of a mean 13 months (P < 0.05) identified by imaging studies had significant impacts on overall survival. Conclusions Calcification or ossification and first recurrence identified by CT and MR imaging studies are significant adverse prognostic factors in primary dedifferentiated liposarcoma of the retroperitoneum. © 2003 Lippincott Williams & Wilkins, Inc.