Pathology

Pathology

Gastric ulcers have similar features to duodenal ulcers but tend to be larger. Fibrosis may result in an ‘hourglass’ deformity of the stomach. Chronic ulcers may erode posteriorly into the pancreas, major vessels such as the splenic artery or rarely into other organs such as the transverse colon. Chronic gastric the incisura angularis; Figures 67.12 and 67.13 ) than on the greater curve and, even when high on the lesser curve, they tend to be at the boundary between the acid-secr eting and the non-acid-secr eting epithelia. With atrophy of parietal cell mass, non-acid-secreting epithelium migrates up the lesser curvature. Pathology

• The most useful clinicopathological classification of gastric cancer is the Laurén classification. In this system there are principally two forms of gastric cancer: intestinal gastric cancer and di ff use gastric cancer (often with signet ring cells). In intestinal gastric cancer, the tumour resembles a carcinoma elsewhere in the tubular gastrointestinal tract and forms poly - poid tumours or ulcers; it probably arises in areas of intestinal metaplasia. In contrast, di ff use gastric cancer infiltrates deeply into the stomach without forming obvious mass lesions but spreads widely in the gastric wall. Not sur prisingly , this has a much worse prognosis. A small proportion of gastric cancers are of mixed morphology . Gastric cancer can be divided into early gastric cancer and advanced gastric cancer. Early gastric cancer is defined as cancer limited to the mucosa and submucosa with or without lymph node involvement (T1, any N); it can be protruding, superficial or excava ted as described in the Japanese classifi - cation ( Figures 67.25 and 67.26 ). This type of cancer is emi - nently curable with 5-year survival rates in the region of 90%. In Japan, approximately one-third of gastric cancers diag - nosed are in this stage. However, early g astric cancer diagnosis in the UK is relatively uncommon as dyspeptic patients are not always referred for endoscopy at an appropriate stage . Advanced gastric cancer involves the muscularis. Its mac - roscopic appearances have been classified by Borrmann into four types ( Figures 67.27 and 67.28 ). Types III and IV are commonly incurable.