Alpha-Fetoprotein (AFP)-Negative Hepatoid Adenocarcinoma of the Stomach and its Associated Uncommon Features With a Review

Hepatoid adenocarcinoma of the stomach is a rare histologic subtype of gastric carcinoma. Morphologically, it shows hepatocyte-like features and the tumor cells can show the expression of alpha-fetoprotein (AFP) in the tumor cells as well as in serum. There are a few AFP-negative hepatoid adenocarcinoma tumors that have been reported in the literature. A 45-year-old male patient presented with abdominal pain. Endoscopy and radiological studies showed an ulceronodular thickening in the antropyloric thickening with lymphadenopathy. He underwent radical subtotal gastrectomy with lymph node dissection. Microscopic examination showed adenocarcinoma with hepatocytic morphology, the presence of lymphovascular and perineural invasion, prominent peritumoral lymphocytic infiltration, multiple metastatic tumor deposit involving regional lymoh nodes and omentum. Adjacent gastric mucosa showed Helicobacter pylori-associated chronic atrophic gastritis with intestinal metaplasia. On immunohistochemistry (IHC), tumor cells were immunopositive for keratin 7, CDX2, and HepPar-1, p53 (focal), and MUC5AC (focal) while immunonegative for AFP, SALL4, MUC2, CD10, and HER2 (ERBB2) was negative. We report this AFP-negative hepatoid adenocarcinoma with its associated uncommon features and discussed the literature review and diagnostic approach.