Malignant lymphoma occurring in the residual stomach following gastrectomy: plus discussion based on the literature in Japan.

Malignant lymphoma of the remnant stomach was diagnosed in a 53-year-old man 8 years after gastrectomy for a perforated gastric ulcer. Endoscopic examination demonstrated protruding lesions spreading over the entire residual stomach, and biopsy revealed malignant lymphoma. Rectal cancer was diagnosed simultaneously. The residual stomach was completely excised, with splenectomy, in parallel with low anterior resection of the rectum. Histological studies revealed that the lesion in the residual stomach was a lymphoma of the diffuse, large-cell type, according to the Lymphoma-Leukemia Study Group (LSG) classification, with positivity for CD20 and CD45RA, leading to a diagnosis of B-cell lymphoma. Helicobacter pylori microorganisms were found on the luminal surface of the tumor. Despite postoperative chemotherapy, the patient died of disseminated lymphoma 34 months later. Although malignant lymphoma occurring in the residual stomach following gastrectomy is rare, particular attention should be given to the possible presence of a malignant tumor when examining the residual stomach following gastrectomy.