Combined Hepatocellular and Cholangiocarcinoma Arising from the Retroperitoneum with Favorable Response to Systemic Chemotherapy with GemOX-B

Abstract

Ectopic liver tissue (ELT) has a reported incidence of 0.24-0.47%. It is most commonly found in sites near the liver, such as hepatic ligaments, omentum, bladder, thorax and retroperitoneum. Rarely, primary liver cancer arises from ectopic liver tissue. We present a case of a combined hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) arising from retroperitoneal ectopic liver tissue in a patient previously treated for hepatitis C. 64 year-old Caucasian male with liver cirrhosis secondary to Hepatitis C successfully treated with Interferon and Ribavirin 10 year before presentation. On surveillance ultrasound, a hypoechoic mass in the porta hepatis was found and subsequently confirmed by computed tomography that demonstrated a 7.1 x 4.3 x 5.9 cm mass causing mass effect on the portal vein, inferior vena cava, duodenum and pancreatic head. Liver function tests, AFP, carcinoembryonic antigen and CA 19-9 were all within normal limits. CA 125 was elevated (839U/mL) and the hepatitis C quantitative RNA was undetectable. Exploratory laparotomy demonstrated a 15 cm mass arising from the retroperitoneum adjacent to the inferior vena cava and portal vein. The tumor did not appear to be arising from the caudate lobe. The pathology was positive for HCC (Hep Par1(+), CK19(+), CK7 focally(+), CEA focally(+), CD34(-), CK20(-), Mart1(-)). Patient received 12 cycles of systemic Gemcitabine and Oxaliplatin and restaging images demonstrated partial response to the treatment. Ectopic HCC is defined as HCC arising from hepatic tissue located outside the liver. In total, HCC has been detected in only 46 of the 110 ELT reported cases. It has been suggested that ELT is more prone to carcinogenesis than the mother liver because it lacks the complete functional architecture necessary for the clearance of viruses and carcinogenic substances. Most ectopic HCC are coincidentally detected due to high AFP levels, an abdominal mass or pain. Nowadays, there are no standard treatment modalities for unresectable combined HCC and CC, due to its mixed histology, these patients are not candidates for either HCC or CC clinical trials. GEMOX chemotherapy (Gemcitabine + Oxaliplatinum) is an active regimen used for mixed primary tumors and its use should be considered for mixed HCC and CC tumors. We herein present this unusual case of ectopic HCC/hepatoma in efforts to emphasize the importance of considering this rare entity in the differential diagnosis of an abdominal mass.