A Case of Gastric Adenocarcinoma with Enteroblastic Differentiation

Abstract

Gastric adenocarcinoma with enteroblastic differentiation is classified as a special type of malignant epithelial tumor. An 80-year-old man was diagnosed as having double gastric cancers on follow-up annual gastrointestinal endoscopy after prior endoscopic cancer therapy. The histopathological examination of the biopsy specimen showed well- or moderately-differentiated tubular adenocarcinoma in both types of lesion. He underwent total gastrectomy and recovered uneventfully. Histopathological findings of the resected specimen showed some atypical cells, partially including clear vesicles, with positive SALL4 and AFP staining in the type 2 lesion, which invaded moderately or highly to lymphatic or venous vessels. The type 0-II a lesion was composed of well-differentiated adenocarcinoma with only mucosal invasion. Although adjuvant chemotherapy with S-1 was started, multiple liver metastases appeared 4 months after surgery, followed by administration of CapeOX. The metastases shrank, but then began to grow again 7 months after the surgery. The second-line regimen, nab-paclitaxel and ramucirumab, also failed after 14 months of administration. Current third-line treatment with nivolumab caused tumor shrinkage, confirmed by CT scan 17 months after the surgery. This disease is supposed to have a very poor prognosis, but the treatment strategy remains controversial because of the insufficient number of patients studied.