Has primary gastric lymphoma become more common?

Primary gastric lymphoma comprised 20% of 119 patients with gastric malignancy seen at our hospital between 1975 and 1980, even when strict criteria were applied to exclude systemic lymphoma patients with gastric involvement. Of the 24 patients with gastric lymphoma, 16 had disease confined to the stomach and contiguous nodes. Eight with massive stomach involvement, but also evidence of distant disease were classified as "probable" primary gastric lymphoma. Symptoms, physical findings, and laboratory studies in the lymphoma patients were similar to those of carcinoma patients. Radiography was more likely to suggest benign conditions in cases with lymphoma. While endoscopy suggested malignant disease in over 80% of lymphoma patients, histologic diagnosis of lymphoma was made first by endoscopy in only 38%. Our data suggest that lymphomas are more common among gastric neoplasms than reported in the past. This cannot be accounted for by referral patterns or by improvement in diagnostic techniques. Although lymphomas appear to be more common, this is not necessarily due to a rise in their incidence. The proportionate increase in lymphomas may be due to the decline in gastric carcinoma or to a true increase in incidence.