ABSTRACT
A 79-year-old man was admitted to our hospital because of increased hepatobiliary enzyme levels. Dynamic computed tomography and magnetic resonance imaging showed a liver tumor measuring 60mm containing fat foci at the cranial aspect of the tumor. We diagnosed the patient with hypovascular hepatocellular carcinoma (HCC) and fat deposition, and performed a caudate lobe resection. Pathology examination revealed two intermingled components: moderately differentiated HCC with fat deposition and neuroendocrine carcinoma (NEC). Primary combined NEC and HCC is extremely rare. To our knowledge, this is the first report of combined NEC and HCC including a fat component. HCC is the most common primary hepatic malignancy with fat. HCC might include fat, even if HCC coexists with another type of cancer. The imaging characteristics of and HCC with another type of cancer vary depending on the amount of each component. We should not simply diagnose such tumors as HCC, but think about the possibilities of HCC with another type of cancer, because there is a fat component.