Hepatic Metastasis from Hepatoid Adenocarcinoma of the Stomach Mimicking Hepatocellular Carcinoma: Diagnostic Challenge

Hepatoid adenocarcinoma (HAC) is a unique type of extrahepatic adenocarcinoma that histologically mimics the appearance of hepatocellular carcinoma (HCC). Hepatoid adenocarcinoma of the stomach has a poor prognosis with increased potential for liver metastasis. HCC and HAC share clinicopathological and immunohistochemical features. The diagnosis of metastatic hepatoid adenocarcinoma to the liver is challenging. It is often misdiagnosed as hepatocellular carcinoma. The diagnostic dilemma is more when the primary tumour is unknown and the first diagnosis is to be established on liver biopsy. Herein, we present the case of a 68-year-old male patient who presented with dysphagia and abdominal discomfort for a three-month duration. Imaging studies showed multiple hypodense lesions in both lobes of the liver. Serum AFP level was markedly elevated to a level of 83,000 ng/ml). A liver biopsy showed atypical polygonal cells in the trabecular pattern. The atypical cells were CK7 negative, CK 20 negative, Hep Par-1 positive and AFP positive. Features were suggestive of hepatocellular carcinoma. Endoscopy showed ulceroproliferative growth in the distal body and antrum of the stomach, a biopsy of which showed atypical cells of similar morphology. The cells were showing focal positivity for CK7, CK20, Hep Par-1 and AFP. On further evaluation, tumour cells in both locations showed positivity for SALL 4. Correlating clinical features, radiology, serum marker values and IHC profile, diagnosis of hepatoid adenocarcinoma of the stomach with liver metastasis was given.