STOMACH (Robbins pp 787)

Benign lesions

Benign lesions in the stomach can be non-neoplastic or neoplastic. The common non-neoplastic lesions found are the hyperplastic polyps. These are just extra cells that grow in clusters and project into the lumen, they have no malignant potential. The neoplastic lesions are the adenomas. These are lesions which have glandular proliferation of the mucosal cells, where the cells are dysplastic. These have malignant potential. Adenomas can have a broad attachment to the mucosa (sessile) or be pedunculated.

Malignant lesions – Gastric carcinoma

Incidence: Incidence is high in Asia, South America, and Eastern Europe. Incidence is dropping in USA/UK/Australia. Prognosis is poor with 5 year survival rate of 20%.

Aetiology: Can be divided into dietary (i.e.: nitrites/nitrosamines, smoked/salted foods), lifestyle (i.e.: smoking, low socioeconomic class), stomach disorders (i.e.: H.pylori, chronic gastritis & intestinal metaplasia, gastric adenoma, Barrett oesophagus), genetic predisposition (i.e.: family history, colon cancer).

Macroscopic appearance of gastric carcinoma: Early gastric tumours are confined to the mucosa and submucosa, whereas advanced gastric tumours extend into the muscularis layer. Gastric carcinomas can progress to the following types of lesions: 1) exophytic/protruded, 2) diffuse/flat/depressed: spreads within the mucosa, 3) excavated: ulcerates through the wall, similar to peptic ulcers. Linitus dysplastica is a rare form of diffuse infiltration of malignant cells throughout the mucosa making the wall rigid.

Microscopic appearance of gastric carcinoma: There are two histologic subtypes of gastric carcinoma: 1) intestinal, 2) infiltrative. The former comprises of glands resembling Ca of colon, and the cells produce mucin. The latter comprise of malignant cells which are scattered throughout the mucosa, cells have signet ring conformation (mucin producing).

Spread of gastric carcinoma: Local (celiac etc), and distal lymph nodes (supraclavicular – Virchows nodes), visceral organs (pancreas, liver, & ovaries  called Krukenberg tumour).

Other types of malignant lesions

Some other types of malignant lesions are:

Lymphomas, Carcinoid (i.e.: neuroendocrine derivative), Leiomyosarcoma.

Category: Pathology Notes