An autopsy case of alpha-fetoprotein-producing large duodenal adenocarcinoma.

We report an autopsy case of a large duodenal adenocarcinoma that produced alpha-fetoprotein (AFP). The patient was a man in his 70s with diabetes mellitus. He presented with epigastralgia and was referred to our hospital. Upper gastrointestinal endoscopy and abdominal computed tomography revealed a large tumor of 11 cm in diameter in the descending limb of the duodenum. A tumor biopsy showed poorly differentiated adenocarcinoma. Although his carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) levels were within the normal range, his AFP levels were significantly elevated (42,078.4 ng/mL). Due to vascular invasion, curative resection was not feasible, and chemotherapy was chosen as the treatment option. After gastrojejunostomy was performed to enable oral intake, one cycle of modified leucovorin/5-fluorouracil/oxaliplatin (mFOLFOX6) therapy was administered. However, it proved ineffective, and the patient's anorexia gradually worsened. Ultimately, he succumbed to the progression of cancer cachexia. Autopsy findings revealed a 14-cm-long duodenal carcinoma primarily located in the duodenal bulb, with direct invasion into the stomach, pancreas, and liver. A pathological examination confirmed a diagnosis of poorly differentiated adenocarcinoma with AFP production. Duodenal cancer is rare, and AFP-producing duodenal cancer is even rarer, with only 21 reported cases, including our own. We present this autopsy case of AFP-producing duodenal adenocarcinoma and review the cases reported in the relevant literature.