Retroperitoneal Liposarcoma: A Comparison of CT Findings with Pathology

Objective To study CT features of retroperitoneal liposarcoma and its different histological subtypes by comparing with the pathological findings, and to make a further understanding of the disease.Materials and Methods CT findings in 22 patients (total 28 case times, including 11 initial and 17 recurrent case times) with primary retroperitoneal liposarcoma were retrospectively analyzed. Preoperative CT findings were compared with pathological results. The correlation of CT signs of different histological liposarcoma with pathology was studied.Results Pathologically, lipoma like liposarcoma (LLS) was seen in 4 patients, while myxoid (MLS) in one, round cell (RCLS) in one, dedifferentiated in 2 (DDLS) and mixed in 20. On CT scans, LLS showed heterogeneous fat density with septum shadow, and MLS presented water density with reticular or island like enhancement on enhanced scans. RCLS displayed as soft tissue mass containing no fat, which was difficult to be differentiated with other soft tissue tumors. DDLS was demonstrated as markedly enhanced soft tissue mass often containing well differentiated lipoma like tissue.Conclusion Retroperitoneal liposarcoma of different histologic subtype carries each own CT characteristics. The CT features depend on the proportion, distribution and mixed pattern of different components within the lesion. Mixed type is most often seen in this study. The knowledge of liposarcoma's CT manifestations is helpful for the preoperative diagnosis and classification of the disease.