Abstract： Background Intravenous leiomyomatosis is a rare neoplasm,and its cardiac extension is often overlooked or misdiagnosed.The purpose of this study was to explore the imaging features of intravenous leiomyomatosis with cardiac extension,especially the value of magnetic resonance imaging in differential diagnosis.Methods Between July 2005 and August 2008,4 cases of intravenous leiomyomatosis with cardiac extension were resected in Cangzhou Central Hospital.Three cases had echocardiography performed,two had post contrast scans of CT performed,and two had MRI performed.Between July 2005 and May 2010,25 cases of histopathologically proven other kinds of tumors involving the inferior vena cava and right atrium were compared for discussion of differential diagnosis.Results Intravenous leiomyomatosis with cardiac extension demonstrated a hyperechoic elongated mobile mass extending from the inferior vena cava to the right atrium with or without evidence of protruding into the right ventricle on echocardiography.The lesion was enhanced heterogeneously on post contrast scans of CT and was of relatively lower density compared to the enhanced blood in the inferior vena cava and right atrium,with common iliac vein and the ipsilateral internal iliac and ovarian veins involved in some cases.The untreated uterus myoma demonstrated enlargement of the uterus with heterogeneous contrast enhancement.On MRI,the lesion looked like a luffa vegetable sponge on FIESTA coronal images and a sieve pore on T2-weighted axial images.All four tumors were removed successfully,and follow up of one to four years revealed no recurrence.The 25 cases of histopathologically proven other kinds of tumors involving inferior vena cava and right atrium had their own imaging features different from those seen on intravenous leiomyomatosis with cardiac extension.With reference to their medical history,differential diagnosis can often be made.Conclusion The imaging appearance of intravenous leiomyomatosis has some unique features,and the luffa vegetable sponge and sieve pore like appearance on MRI may be helpful for differential diagnosis.