Dedifferentiated Liposarcoma with Abrupt Transition of Low-Grade and High-Grade Dedifferentiated Components :A Case Report
Abstract Background: Dedifferentiated liposarcoma (DDLPS) is a unique subtype ofliposarcoma, which has obvious histological heterogeneity. In affected patients, the condition typically manifests as the dedifferentiation of high-grade histological morphology, but it may also manifest as the dedifferentiation of low-grade histological morphology. In some cases, unique histological or immunophenotypic characteristics are observed. We describe, herein, a rare case of dedifferentiated liposarcoma, in which the high-grade and low-grade dedifferentiated components coexisted with a relatively sharp transition in pathology.Case presentation: A 69-year-old woman with severe abdominal pain lasting for 1 hour presented to our hospital. Physical examination revealed a mobile large left abdominal mass, Magnetic resonance imaging (MRI) scan showed a huge mass with typical fat components and the non-fatty nodule in the left retroperitoneal cavity. After laparotomy, histologic analysis of the specimens could find the ALT/WDLPS and DDLPS components. Fluorescence in situ hybridization (FISH) analysis suggested the presence of MDM2 gene amplification. These findings supported a diagnosis of DDLPS.Conclusion: In our case, the high-grade and low-grade dedifferentiated components coexisted with a relatively sharp transition in pathology. We hypothesize that low-grade dedifferentiation may be a precursor to high-grade dedifferentiation. MRI images cannot distinguish the two components.