Metachronous Gastric Metastasis of Hepatocellular Carcinoma Mimicking Early Gastric Cancer and Detected on Esophagogastroduodenoscopy: A Case Report and Literature Review

Background: Although extrahepatic metastasis of hepatocellular carcinoma (HCC) is common in the lungs and bones, metachronous gastric metastasis of HCC, which is initially detected in the form of multiple small gastric polyps, is extremely rare. Case presentation: A 62-year-old man was diagnosed with HCC by abdominal computed tomography (CT), but the patient received only intermittent treatment. After 15 months, esophagogastroduodenoscopy revealed multiple 0.3–0.6 cm sessile polyps in the midbody and distal body of the stomach; these findings were not documented in the report of the previous examination. Microscopically, the stomach biopsy specimen revealed tumor cells with prominent nuclear atypia arranged in trabecular and solid patterns and infiltrating the gastric mucosa. However, no signs of glandular intraepithelial neoplasia were found in the gastric mucosa. Immunohistochemically, the tumor was positive for HepPar-1 and glypican-3 and negative for SALL4, cytokeratin-7, and cytokeratin-20, consistent with the immunophenotype of the primary HCC. Therefore, the gastric polyps were diagnosed as metachronous gastric metastasis of HCC. The patient was administered sorafenib, but follow-up CT showed radiological disease progression. He died 3 months after being diagnosed with metachronous gastric metastasis of HCC. Conclusions: Based on our experience, this rare case might help clinicians and pathologists avoid misdiagnosing gastric metastasis of HCC as primary gastric adenocarcinoma with hepatoid differentiation and prevent inappropriate treatment. In patients with HCC, biopsy of newly detected gastric polyps should be considered even when they appear benign on endoscopy, to exclude metastatic involvement.