Objective To explore the CT features of primary retroperitoneal liposarcoma.Methods A retrospective analysis of pathologically confirmed primary retroperitoneal liposarcoma was done.Results Tumors were located in left retroperitoneal space in 16 cases,in right retroperitoneal space in 10 cases,and in median retroperitoneal space in 3 cases.The maximum diameter ranged from 9-40 cm,with an average of (17 ±8) cm.Tumors were round in 8 cases,oval in 10 cases and irregular in 11 cases.The boundary of tumor was clear in 10 cases.CT plain scanning was mixed density in 20 cases,uniform density in 9 cases;Tumors of necrotic cysts in 11 cases,and with calcification in 9 cases;Enlarged intraperitoneal and retroperitoneal lymph nodes were found in 6 cases and intrahepatic metastases in 3 cases.The solid part was mild to moderate enhancement.Pathologically of the 29 cases,7 were dedifferentiated,4 were mucous,5 were polymorphic,1 1 were well differentiated and 2 were mixed.Conclusion The CT examination of primary retroperitoneal liposarcoma is of great value in locating tumor and judging the relationship between tumor and adjacent organs.

Arrhythmogenic cardiomyopathy (ACM), a fatal heart disease characterized by fibroadipocytic replacement of cardiac myocytes, accounts for 20% of sudden cardiac death and lacks effective treatment. It is often caused by mutations in desmosome proteins, with Desmoglein-2 (DSG2) mutations as a common etiology. However, the mechanism underlying the accumulation of fibrofatty in ACM remains unknown, which impedes the development of curative treatment. Here we investigated the fat accumulation and the underlying mechanism in a mouse model of ACM induced by cardiac-specific knockout of Dsg2 (CS-Dsg2 ^-/-). Heart failure and cardiac lipid accumulation were observed in CS-Dsg2 ^-/- mice. We demonstrated that these phenotypes were caused by decline of fatty acid (FA) β-oxidation resulted from impaired mammalian target of rapamycin (mTOR) signaling. Rapamycin worsened while overexpression of mTOR and 4EBP1 rescued the FA β-oxidation pathway in CS-Dsg2 ^-/- mice. Reactivation of PPARα by fenofibrate or AAV9-Pparα significantly alleviated the lipid accumulation and restored cardiac function. Our results suggest that impaired mTOR-4EBP1-PPARα-dependent FA β-oxidation contributes to myocardial lipid accumulation in ACM and PPARα may be a potential target for curative treatment of ACM.