[A case of primary gastric malignant lymphoma perforated immediately after administration of chemotherapy].

A 77-year-old man was admitted to our hospital with complaints of abdominal pain and body weight loss. Esophagogastroduodenoscopy on admission revealed large ulcerative tumor in the entire region from upper to lower body of the stomach. We diagnosed gastric malignant lymphoma, diffuse large B-cell type and determined stage IV according to the Lugano International Conference classification. Due to gastric perforation occurred on day 4 of chemotherapy, total gastrectomy and partial resection of the transverse colon were performed. Complete remission was achieved by 2 cycles of postoperative chemotherapy together with rituximab.