Carcinoma of the stomach (CS) or stomach cancer is one of the most common forms of malignant tumors of a mankind. Men suffer from CS in 2-2.5 times oftener than women. The highest morbidity of CS is registered in Japan.
Background processes include –
- chronic atrophic gastritis especially of autoimmune origin
- chronic atrophic gastritis after resection of the stomach (chronic atrophic gastritis of the gastric stump) with intestinal metaplasia – the rate of malignant transformation (RMT) is about 30%
- hypertrophic gastropathy (Menetrier’s disease) – RMT is about 10%
- Precancerous (premalignant) changes:
- adenomatous polyps
- chronic peptic ulcer
Menetrier’s disease is characterized by abnormally thickened (giant) gastric folds with multiple growing micro polyps on their surface. The origin of the disease is not known well. Histologically the mucous layer of the folds contains a small quantity of the main and parietal cells but an increased proportion of mucus producing cells. Menetrier’s disease due to prominent cellular proliferation is considered as a premalignant lesion.
In accordance with Lauren’s classification (1965), all morphological types of CS are differentiated into 2 groups: CS of the diffuse type and CS of the intestinal type.
Carcinoma of Stomach of the diffuse type usually develops in the fundus of the stomach and is common mostly for middle-aged and even young persons with a high proportion of women. This form of CS is characterized by clear genetic predisposition. Morphologically CS of the diffuse type manifests itself in the intensive infiltrative growth with the prominent thickening of the stomach wall (endophytic growth). Histologically this form of CS is represented by scirrhous adenocarcinoma or signet-ring cell carcinoma.
In scirrhous adenocarcinoma, malignant epithelial cells do not form glands but cause the intensive secondary growth of connective tissue (“fibrosis cancer”). Due to it, the consistency of the impaired tissue is very firm and rigid.
The signet-ring cell carcinoma is characterized by the intensive accumulation of a mucous in the cytoplasm of tumorous cells with prominent compression of the nucleus. The extreme stage of mucus accumulation leads to the formation of a mucoid carcinoma with an extracellular accumulation of a mucous.
Both forms of diffuse CS are attributed to undifferentiated types of adenocarcinomas and have the bad prognosis.
Diffuse form of CS is characterized by the long asymptomatic (subclinical) period of its development since the tumor does not close the lumen of the stomach and hence does not evoke impassability of the meal. The first clinical symptom is conditioned by ulceration of the mucosa with gastric bleeding. However, this complication develops in the last stages of the disease and due to it a diffuse form of CS is characterized by bad prognosis.
Carcinoma of Stomach of intestinal type predominates among all other forms of CS. It develops mainly in aged men and affects predominantly the antral portion of the stomach. A tumor develops from the sites of intestinal metaplasia or adenomatous polyps. CS of the intestinal type usually manifests itself exophytic growth in the form of a mushroom (fungous form), a polyp, a saucer-shaped or crateriform ones.
Histologically CS of the intestinal type usually represents itself the different kinds of adenocarcinomas (trabecular, tubular, papillary, mucous). Rarer undifferentiated types of adenocarcinoma with diffuse growth may occur.
As carcinoma of intestinal type is localized mainly in the antral portion and characterized by exophytic growth, the most typical and early symptom of the process is cancerous stenosis of the exit of the stomach with impassability of the meal. This complication will produce a very typical and early symptom – vomiting with the meal eaten the day before. As a result of it, the patient will immediately come to a medical center and the diagnosis of CS will be put in early stages of the process. In view of this CS of the intestinal type is characterized by more or less good prognosis.
Complications and causes of death:
- ulceration of gastric wall with gastric bleeding;
- perforation of the wall of the stomach with subsequent peritonitis;
- cancerous stenosis of the pylorus with impassability of the meal;
- invasion into surrounding organs (pancreas, large intestine, gall bladder, diaphragm);
- wide metastatic spreading not only in lymphatic nodes but also hematogenic metastases in the liver, lungs, brain, bones, kidneys, adrenal glands, pancreas;
- carcinomas cachexia with progressive atrophy of the myocardium and heart failure.