| Objective To investigate the clinicopathological features,immunophenotypic,genetic features and essentials for diagnosis and differential diagnosis of retroperitoneal dedifferentiated liposarcoma(DDLPS).The purpose of this study is to improve the understanding of DDLPS and provide evidence for clinical treatment and prognosis evaluation.Methods The clinical and histological characteristics of 44 cases of retroperitoneal DDLPS from the Affiliated Hospital of Qingdao University between January 2009 and November 2019 were retrospectively reviewed.The expressions of CD117,DOG-1,S100,CD34,CD99,SMA,p16,MDM2,CDK4,STAT6,MUC4,MyoD1,myogenin,?-Catenin,and ALK were detected by immunohistochemistry and MDM2 gene amplification was evaluated by fluorescence in situ hybridization(FISH).Comparison between groups by single factor survival analysis,to test whether the histological grade of dedifferentiated components in DDLPS is related to the overall survival(OS)and progression free survival(PFS),and test whether the invasiveness of DDLPS is related to the overall survival(OS)and progression free survival(PFS).Results The average age of 44 patients was 57.5 years(38-69 years),and the median age was 59 years.The maximum diameter of the tumor was 5-50 cm,with an average of 23.4 cm;18 cases had clinical symptoms(abdominal pain,abdominal distention or low back pain),26 cases were found by routine physical examination,and 5 cases had a history of retroperitoneal WDLPS surgery;all cases were operated to remove the focus,32 cases of tumor invasion of adjacent tissues and organs were operated on in combination with adjacent affected organs.Pathologically,the tumor displayed highly differentiated liposarcoma components,and the distribution boundary between dedifferentiated and highly differentiated areas was clear.It showed scattered large and deeply stained heterotypic cells and multinucleated cells,some interstitial mucinous change,branching or arcuate small vessels.The histological features of dedifferentiated components were rather diverse and heterogeneous among which 16 cases were pleomorphic undifferentiated sarcoma-like,7 were high-grade myxofibrosarcoma-like,3 were high-grade fibrosarcoma-like,5 were fibromatosis-like,3 were low-gradefibromyxoid sarcoma-like,3 were solitary fibromatosis-like,1 was inflammatory myofibroblastoma-like,2 were osteosarcoma-like,and 3 were leiomyosarcoma-like,and 1 was rhabdomyosarcoma-like.In addition,3 cases were observed with meningioma-like whirlpool nodule.Immunohistochemistry showed that the positive rates of p16,MDM2 and CDK4 were 97.7%,93.2% and 88.6% respectively.The positive rate of simultaneous expression was 81.8%,and 97.7% of them expressed both at the same time.MDM2 gene amplification was detected in 95.5% cases.However,single factor survival analysis showed that the histological grade of dedifferentiated components in DDLPS was not related to OS(P = 0.1624,P > 0.05),nor to PFS(P = 0.0618,P > 0.05).Whether DDLPS invades the surrounding organs was not related to OS(P = 0.1624,P > 0.05),nor to PFS(P = 0.0618,P > 0.05).Conclusion Retroperitoneal DDLPS are often found in the elderly with a large size and high recurrence rates.The histological morphology of dedifferentiated components of DDLPS is diverse,which is easy to cause misdiagnosis.Immunostaining for p16,MDM2,CDK4 and FISH for MDM2 amplification have important diagnostic values.We found that the histological grade of dedifferentiated components was not related to postoperative recurrence and survival.Radical resection with multiple organ resection is an important mean to improve the prognosis. |
PDF Full Text Request