Collision of malignant lymphoma and multiple early adenocarcinomas of the stomach.

An unusual case of coexisting malignant lymphoma and adenocarcinoma of the stomach is described. A 61-year-old man with weight loss, malaise, and tarry stool demonstrated diffuse lymphoma, large-cell type, and two early gastric carcinomas. Each of the two early carcinomas collided with malignant lymphoma, respectively. Two histologically different tumors were precisely diagnosed preoperatively in this case. Frequent endoscopy with biopsies from various sites of the lesion is important in achieving a correct diagnosis.