What happened, in summary

A 76-year-old woman had 2 months of epigastric pain before endoscopy found a large polypoid tumor at the gastric cardia. Her serum alpha-fetoprotein, or AFP, was markedly elevated. CT showed a stomach mass without abnormalities in the liver or bile ducts, and she underwent proximal subtotal gastrectomy.

Pathology revealed an unusual mixed malignant tumor. One component was gastric adenocarcinoma with hepatoid features, meaning that the cancer cells resembled liver cells and produced AFP. A second sarcomatous component contained spindle-shaped and cartilage-like cells. Together, these findings established the diagnosis of gastric carcinosarcoma with AFP-producing hepatoid adenocarcinoma. The tumor had invaded the submucosa, while the sampled lymph nodes showed no metastases. One week after surgery, the serum AFP level had fallen sharply.

No adjuvant chemotherapy was given because her general condition was poor and she and her family declined further treatment. Despite surgery, the cancer later metastasized. She died 8 months after the gastrectomy. The case highlights an exceptionally rare gastric tumor combining two aggressive histologic patterns,