A rare case of alpha-fetoprotein-producing early gastric cancer.

Most of the alpha-fetoprotein-producing gastric cancer is advanced at the time of presentation, and alpha-fetoprotein-producing early gastric cancer is extremely rare. Alpha-fetoprotein-producing early gastric cancer was confirmed by immunohistochemistry and serum analysis of alpha-fetoprotein concentration. Alpha-fetoprotein carbohydrate chain microheterogeneity was further evaluated by lectin binding specificity. A 71-year-old-male patient underwent total gastrectomy due to a depressed type of gastric cancer in the upper third of the stomach. There was no evidence of synchronous liver metastasis and hepatitis. Histological examination revealed that the tumor invasion was limited to the submucosal layer, and that the tumor consisted of both well-differentiated, papillo-tubular growth areas and trabecular and medullary growth areas resembling hepatoid carcinoma. Immunohistochemically, alpha-fetoprotein and cytokeratin localization were confirmed in the cancer cells, whereas simultaneous localization of carcinoembryonic antigen, carbohydrate antigen 19-9, and human chorionic gonadotropin could not be observed. The elevated preoperative serum alpha-fetoprotein concentration (113 ng/mL) promptly decreased to and remained within normal levels postoperatively (3.6 ng/mL). The predominance of a strong-bound fraction with lectin, which was demonstrated by lens culinalis agglutinin affinity chromatography, suggests that the alpha-fetoprotein carbohydrate chain species in the present case was a hepatic type. The patient received adjuvant intravenous chemotherapy consisting of 5-fluorouracil and cisplatin, and has been further supported by oral 5-fluorouracil administration. The patient has been disease free for 15 months following surgery. We report here a rare case of alpha-fetoprotein producing early gastric cancer. The alpha-fetoprotein carbohydrate phenotype analysis helps to consider the primary differentiation of alpha-fetoprotein-producing gastric cancer.