A case of synchronous primary cardiac dedifferentiated liposarcoma and papillary renal carcinoma is presented. The occurrence of typical areas of round cell liposarcoma made the pathological diagnosis of the sarcoma relatively easy; however the neoplasm was not diagnosed correctly before the autopsy. Cardiac liposarcoma is a very rare primary malignant neoplasm and its diagnosis based on image procedures may be extremely difficult especially at non-advanced stage of disease.