The authors compare a rare case of acute onset Gastric Lymphoma with that present in the literature. The patient, a white 67 year-old man, was admitted to hospital in severe general condition. On CT scan an opacity of the pleura and a subtotal collapse of the left lung associated with a mass infiltrating the diaphragm, the gastric fundus and pancreas were seen. After 48 hours from the admission an operation was performed. The abdominal mass infiltrating the stomach, the spleen and the left thorax was resected en-bloc by laparotomy. A Boulau drainage was inserted. The histology showed an high malignant, diffused, big cell lymphoma. The patient was discharged 23 days later after a regular postoperative course. Surgery can be necessary, sometime curative in gastric lymphomas while long term result and quality of life could be improved by chemotherapy.