Liver Metastasis of Hepatoid Colonic Adenocarcinoma: A Rare and Unusual Entity With Poor Prognosis and Review of the Literature

Hepatoid adenocarcinoma (HAC) is rare and was first reported as α-fetoprotein (AFP)-producing tumor. It is an important variant of extrahepatic adenocarcinoma with clinicopathological presentation mimicking hepatocellular carcinoma and carries exceedingly poor prognosis. HAC most commonly originates in the stomach, and less commonly in the ovary, esophagus, lung, among other organs. HAC originating in the colon is exceedingly rare. Here we report such a case of a 63-year-old man presented as decompensated liver failure with jaundice and weakness. Computed tomography (CT) imaging findings showed multiple lesions in the liver with ascites and descending colonic mass suspicious for malignancy. The flexible sigmoidoscopy showed a 1.5 cm mass in the descending colon, and biopsy showed superficial fragments of tubular adenoma, but could not exclude deep invasive carcinoma. A liver biopsy was performed and showed a carcinoma with morphologic features resembling hepatocellular carcinoma. The tumor cells were positive for glypican-3, MOC31, CDX2, SATB2 and CK20, negative for arginase-1, p63, synaptophysin and chromogranin. Ki-67 highlighted 80% of the tumor cells. The pathology diagnosis was liver with metastatic hepatoid adenocarcinoma consistent with colonic primary. The patient experienced a rapid worsening of his liver function and died 3 weeks later of hepatic failure without any surgery and chemotherapy. A subsequent literature review of the 17 reported cases of HAC showed that this type of cancer frequently metastasizes to the liver with an astonishingly poor prognosis with eight patients died of the disease in less than 5 months after the diagnosis was made. Radical surgery followed by adjuvant chemotherapy with chemotherapy regimen used for colorectal cancer or primary hepatocellular carcinoma may be the treatment option for colorectal HAC.