Abstract
The histopathology and clinical presentation of 19 cases of primary gastrointestinal lymphoma is described. Our patients are similar to others in the Middle East but have a lower incidence of diarrhoea and malabsorption. All revealed a widespread chronic inflammatory background. Four patients with primary gastric lymphoma had endoscopic biopsies from the duodenum; these biopsies were completely free from tumour but showed a moderate to severe diffuse lymphoplasmacytic infiltrate. Electron microscopy shows that tumour cells penetrate basement membranes and invade the epithelium which becomes thin and attenuated. Substances which inhibit lymphocyte tropism might be useful in preventing intestinal ulceration. The MALT concept has been found useful in classification of the tumours. Two patients with unusual mesenteric node histology are described and it is thought that the appearances may indicate a substantial capacity for differentiation in the group of tumours.