A 67-year-old man was admitted to our hospital because of a large liver tumor revealed by ultrasonography. Laboratory data showed increased serum levels of alpha-fetoprotein (AFP) and des-gamma-carboxy prothrombin (DCP), which are tumor markers for hepatocellular carcinoma. In addition, the serum cholesterol level was extremely high. Endoscopic examination revealed advanced gastric cancer. Histological findings of the stomach and liver tumor showed they were both hepatoid adenocarcinomas and were both positive for antibodies against AFP as well as DCP, suggesting that the tumors were gastric cancer with liver metastasis. Moreover, 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a key enzyme for regulation of cholesterol synthesis, was upregulated in the tumor tissues. Accordingly, we diagnosed this patient with AFP- and DCP-producing gastric cancer accompanied by paraneoplastic hypercholesterolemia. Paraneoplastic hypercholesterolemia is sometimes seen in hepatocellular carcinoma, but never in gastric cancer. This case is interesting because of the feature of hepatoid adenocarcinoma.
Keywords: 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase; Alpha-fetoprotein (AFP); Des-gamma-carboxy prothrombin (DCP); Hepatoid adenocarcinoma; Hypercholesterolemia; Paraneoplastic syndrome.