Alpha-fetoprotein-producing intramucosal gastric cancer found during examination of metastatic lymph nodes

Endoscopic resection has been applied as an absolute indication for early gastric cancer showing intramucosal cancer ≤ 2 cm in diameter, differentiated-type adenocarcinoma without ulcerative findings. We describe the case of a 76-year-old man who underwent radical gastrectomy for alpha-fetoprotein-producing gastric cancer, in which the depth of invasion was clinically diagnosed as T1a after lymph node metastases were detected. Upper gastrointestinal endoscopy revealed a type 0–IIc tumor nearly 10 mm in diameter at the antrum. Computed tomography showed a 47-mm nodule along the common hepatic artery and a 22-mm nodule in the infrapyloric area. Both were pathologically confirmed as adenocarcinoma by endoscopic ultrasound-guided aspiration. No evidence of malignancy elsewhere was seen on ¹⁸F-fluorodeoxyglucose positron emission tomography. Serum alpha-fetoprotein level was elevated. Postoperatively, microscopic examination revealed moderately differentiated adenocarcinoma confined to the mucosal layer without lymphovascular involvement. Immunohistochemical examination for alpha-fetoprotein revealed that the metastatic nodes were positive despite the primary tumor being negative. The patient died of exacerbation of myelodysplastic syndrome 5 years 8 months postoperatively with no recurrence. Our experience suggests the need for further studies to validate whether the indications for endoscopic resection can apply to alpha-fetoprotein-producing gastric cancer in the same manner as to conventional gastric cancer.