Metastatic gastrointestinal hepatoid adenocarcinoma of the liver: a high-grade carcinoma that is easily confused with primary hepatocellular carcinoma

Abstract

Objective: To investigate the clinicopathologic and immunophenotypic features of metastatic gastrointestinal hepatoid adenocarcinomas in the liver. Methods: Eight cases of hepatic metastatic gastrointestinal hepatoid adenocarcinoma diagnosed at the Affiliated Drum Tower Hospital, Nanjing University Medical School from January 2009 to January 2019 were retrospectively analyzed. The clinical data, histopathologic features and immunohistochemical (IHC) characteristics performed by EnVision method were analyzed. Results: There were five males and three females with a mean age of 66 years. The primary sites included one case each from the distal esophagus and the right colon, and the other six cases were from the stomach. Pre-treatment serum AFP levels were increased in four patients, normal in two, and was not known in two other patients. Liver metastases occurred in all eight patients at initial diagnosis. Microscopically, the primary tumor was composed of areas showing hepatic differentiation with or without typical adenocarcinoma component; and the areas with hepatic differentiation morphologically resembled hepatocellular carcinoma (HCC). IHC staining showed variable expression of HCC markers such as Glypican 3, AFP, SALL4 and HepPar-1, and gastrointestinal adenocarcinoma markers such as CK19, CDX-2 and Villin in both the primary and metastatic foci of hepatoid adenocarcinoma. Conclusions: Hepatoid adenocarcinoma in the digestive tract gives rise to only non-specific symptoms, and shows high propensity for invasion and metastasis. When liver metastasis is the presenting symptom, it is difficult to distinguish metastatic hepatoid adenocarcinoma from the primary HCC based on histopathologic characteristics alone. The accurate diagnosis of metastatic hepatoid adenocarcinoma in the liver requires combination of clinical, radiologic, histopathologic and IHC findings.