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Gastric mass

Introduction
Cause
Examine
Diagnosis

Introduction

Introduction In the advanced stage of gastric cancer in the elderly (intermediate and advanced stage), there may be tenderness in the upper abdomen, fullness or mass in the stomach area, hard and fixed, and the surface is uneven and nodular.

Cause

Cause

(1) Causes of the disease

The pathogenesis of gastric cancer is long and complicated. There is currently no single factor that has proven to be a direct cause of human gastric cancer. Therefore, the occurrence of gastric cancer is related to many factors. Dietary factors are the focus of research, and some surveys have shown that high-salt, high-fragrance foods, polycyclic aromatic hydrocarbon compounds produced in cooking, nitroso compounds, mycotoxins, some grains and food additives are carcinogenic.

1. Nitroso compounds: nitroso compounds are a large class of chemical carcinogens, among which non-volatile nitrite amines such as N-methyl N-nitro N-nitrosoguanidine (MNNG), N-B N-nitrosoguanidine (ENNG) can induce gastric adenocarcinoma in rats and dogs, and precancerous lesions such as intestinal mucosa and dysplasia can be observed. Naturally occurring nitroso compounds are extremely minor. Its main source is the endogenously synthesized nitroso compound in the body. The nitroso compound can also be synthesized under the condition of low pH of gastric juice. When gastric mucosal lesions occur, such as gastric gland atrophy, parietal cells decrease, and gastric juice pH increases, gastric bacteria can accelerate the reduction of nitrate to nitroso compound. . Thus, human gastric mucosa can be directly attacked by nitroso compounds under normal or damaged conditions.

2. Polycyclic aromatic hydrocarbon compounds: Carcinogens can contaminate food or form during processing. For example, Iceland is a country with high incidence of gastric cancer. Residents mostly live in fisheries and animal husbandry, and have the habit of eating smoked fish and smoked lamb. Analysis of samples of smoked fish and smoked lamb found that these foods have a large number of carcinogenic substances, including polycyclic aromatic hydrocarbon compounds such as 3, 4-benzoquinone. A large number of animal experiments have shown that the experimental animals are also carcinogenic to the smoked food.

3. Dietary factors: China's gastric cancer case matching research results show that high salt diet, pickled foods, fried foods, three meals irregularly, fast eating, eating too much, eating hot food, etc., increase the incidence of gastric cancer Dangerous. Ingestion of high concentrations of salt can damage the gastric mucosal barrier, causing mucosal cell edema and loss of glands. The simultaneous administration of high salt in the carcinogenic nitroso compound can increase the gastric cancer induction rate, and the induction time is also short, which promotes the occurrence of gastric cancer.

Fresh vegetables, fresh beans, soybeans and their products, fresh fish, meat, eggs, milk can reduce the risk of gastric cancer. The consistency of epidemiological studies around the world shows that fresh vegetables and fruits have protective effects against gastric cancer. Fresh vegetables and fruits contain many nutrients needed by the human body, especially vitamins have anti-cancer effects.

These substances compete with carcinogens to eliminate the formation of free radicals in the body, degrade poisons, protect DNA, protein macromolecules from carcinogens, stabilize cell membranes, and promote normal cell differentiation to achieve anticancer effects. Vitamin C has a strong ability to block nitroso compounds, and beta-carotene has antioxidant capacity and can be converted into vitamin A in the small intestine. Maintain cell growth and differentiation. Therefore, these two types of vitamins are likely to reduce the incidence of gastric cancer by blocking carcinogenesis and increasing cell repair ability.

4. Helicobacter pylori: Helicobacter pylori infection is associated with gastric cancer, based on the following reasons: Helicobacter pylori is rarely isolated in normal gastric mucosa, and the infection rate of Helicobacter pylori is increased with the increase of gastric mucosal lesions. It is currently believed that Helicobacter pylori is not a direct carcinogen of gastric cancer, but a condition that promotes the development of the disease through the injury of the gastric mucosa and increases the risk of gastric cancer. Helicobacter pylori releases a variety of cytotoxic and inflammatory factors and participates in local immunity. In the serum before the determination of gastric cancer patients, the positive rate of Helicobacter pylori antibody was significantly higher than that of the control group, which was a risk factor for gastric cancer.

In addition, smoking, genetic, psychological factors, trace elements, some chronic diseases such as chronic atrophic gastritis (CAG), intestinal mucosal intestinal metaplasia (IM) and dysplasia (DYS) have been reported, and are also associated with gastric cancer.

(two) pathogenesis

Precursors of gastric cancer can be divided into two categories: precancerous conditions and precancerous lesions. Gastric diseases have a related relationship with benign gastric diseases, and there is a risk of developing gastric cancer, but it is not necessarily cancerous or the former refers to the final destination of these diseases, and the latter refers to pathological changes of transformed cancer.

1. Precancerous state of gastric cancer

(1) Chronic atrophic gastritis: atrophic gastritis is a common chronic gastric disease. The rate of gastroscopy in the high-risk area of gastric cancer is as high as 80%, and the mortality rate is positively correlated with the prevalence of atrophic gastritis. The degree of atrophic gastritis is heavy, and the detection rate of intestinal metaplasia is high. The population of high and low incidence areas of gastric cancer in 8 provinces of China, the long-term follow-up (more than 10 years) atrophic gastritis cancer rate of up to 10%. Pathological features Atrophic gastritis occurs in the antrum of the stomach, chronic mucosal inflammation with atrophy of the gland. May have intestinal metaplasia or abnormal epithelial hyperplasia.

(2) Gastric ulcer: At present, most authors believe that chronic gastric ulcer will develop cancer, and the incidence rate is about 0.5% to 2%. The pathological criterion for judging gastric cancer is that the mucosal membrane is completely destroyed, the mucosa of the ulcer is adhered to the muscle layer, and the muscle layer at the bottom of the ulcer is completely destroyed by dense fibrous connective tissue and granulation tissue. The mechanism is that the inflammation, erosion, regeneration and repair of the atypical epithelial cells on the edge of the ulcer are not mature enough, and the cells are prone to carcinogenesis under the action of carcinogens. In addition, the cancer that occurs at the edge of the ulcer, the proportion of signet ring cell carcinoma is high and the common gastric cancer group, this feature is also an evidence to support the canceration of ulcers.

(3) Residual gastric cancer: Residual stomach as a precancerous state, its relationship with gastric cancer has also been paid attention to. It is generally claimed that it should be a cancer that occurs in the residual stomach for more than 10 years after benign resection of the stomach. In a broad sense, including cancer patients who have cancer in the residual stomach 15 years after surgery, collectively referred to as residual gastric cancer. The incidence of residual gastric cancer is about 1% to 5.5%. Biopsy pathological examination found that chronic atrophic gastritis with intestinal metaplasia and epithelial cell atypicality in the anastomotic site, combined with alkaline intestinal reflux, bile pancreatic juice reflux, low acid environment, gastric motility disorder, bacteria Reproductive growth and synthesis of nitroso compounds are important factors in the development of gastric cancer. These may become prodromal lesions of gastric cancer. In addition, cancer that occurs after gastrojejunostomy is often associated with hyperplastic polyps, which are accompanied by cystic changes in the glands.

2. Gastric cancer precancerous lesions

(1) dysplasia: also known as atypical epithelial hyperplasia (atypical epithelia). Heterotypic epithelial hyperplasia is a heterotypic (atypical) change in the glandular duct structure of the gastric mucosa and the loss of normal state of epithelial cells. It is different from morphological and regenerative and simple hyperplasia, and the histological boundary is between the benign and malignant. The basic pathological features include three aspects: 1 atypicality of cells, including increased proportion of nucleoplasm, nuclear atypia, etc.; 2 abnormal differentiation, including reduction or even disappearance of goblet cells in metaplastic epithelium, loss of gastric gland Differentiation characteristics of the body (pyloric gland or thymus gland), as well as changes in secretion or changes in secretion traits; 3 structural disorders, including irregular gland shape, back-to-back and co-wall phenomenon, glandular branching, budding, papillary Hyperplasia and so on.

In recent years, studies on dysplasia in China have been divided into 5 types, namely adenoma, crypt, regenerative, spheroidal and saclike. The adenoma type is derived from the intestinal metaplasia epithelium, which starts from the superficial layer of gastric mucosa and becomes a highly differentiated adenocarcinoma after canceration. The crypt type also occurs in the intestinal metaplasia gland, which begins in the deep layer of the glandular crypt and becomes cancerous. Highly differentiated or moderately differentiated adenocarcinoma. Regenerative type of regenerating duct and epithelium after gastric mucosal defect, mainly developed into poorly differentiated adenocarcinoma or undifferentiated adenocarcinoma. The ball-like change occurs between the pyloric intestine gland or the intestinal metaplasia glandular epithelium, showing a large amount of mucus in the cytoplasm, and the cell body is spherical, which will develop into signet ring cell carcinoma. The saccular gland is expanded with an epithelium that is atypical and exists only in the vicinity of the cancer. The detection rate of heterotypic epithelial hyperplasia in high-incidence areas of gastric cancer can reach 20%, which is higher than that in low-incidence areas. The detection rate increases with age, and more males than females occur in gastric antrum and stomach horn, focusing on cancer. Heterotypic hyperplasia can be 5% or so after 5 to 10 years of canceration.

(2) Gastric mucosa intestinal metaplasia: the intrinsic mucosal epithelium of the stomach and the fundus glands, the cardia gland, and the pyloric gland are converted into intestinal epithelial cells. Metaplastic epithelial cells are composed of absorptive cells, with cup-shaped cells and Pan's cells in between. Intestinal metaplasia with gastric cancer is 60% to 100%, and the predilection site is consistent. According to the different enzyme content and activity of intestinal metaplasia, the high activity of enzyme-containing enzyme is called complete intestinal metaplasia, and the one with less enzyme is called incomplete intestinal metaplasia. Those with complete type differentiation are small intestine type intestinal metaplasia, and those with incomplete type differentiation are large intestine type intestinal metaplasia. Two kinds of intestinal metaplasia can exist in the gastric mucosa at the same time. The small intestine type is more common in benign lesions, and the large intestine type is more common in the side of the cancer. It is considered that the large intestine type metaplasia is a precancerous lesion of gastric cancer.

3. Early gastric cancer

(1) General type:

1 uplift type (type I): the prominent focus of the cancerous lesion protrudes into the stomach cavity, which is polypoid and the height exceeds 0.5cm.

2 superficial type (type II): superficial cancerous foci, no obvious uplifts and depressions, divided into 3 subtypes:

Type IIa: superficial bulge type with a height below 0.5 cm.

Type IIb: superficially flat.

Type IIc: shallow depression type, the depression does not exceed 0.5cm.

3 concave type (type III): also known as ulcer type, the depression is above 0.5cm.

4 mixed type: There are two forms of coexistence, with IIc+III, IIc+IIa as the most.

Among the 3 types, the most common type is the concave type, and the flat type is the least.

(2) Histological type: According to the morphological classification, it is divided into papillary duct adenocarcinoma, duct gland mucinous adenocarcinoma and cordoid adenocarcinoma. According to the classification of gastric cancer research association, tubular adenocarcinoma is the most common, accounting for 60%, followed by poorly differentiated gland. Cancer accounts for 15%, papillary adenocarcinoma, undifferentiated carcinoma is rare, and mucinous cell carcinoma accounts for about 5%.

(3) Staging: The Japanese Endoscopy Society proposed in 1962 that the depth of gastric cancer tissue infiltration was limited to the mucosa or submucosa, regardless of the size of the tumor or the presence or absence of lymph node metastasis as early gastric cancer.

In the early gastric cancer, the area with the largest diameter of 5.1 to 10 mm is called small-gastric cancer, and those below 5 mm are microgastric cancer, ultra microcarcinoma, also known as "spotted cancer" or "a little bit." "Pig point carcinoma" refers to the endoscopic biopsy confirmed the diagnosis of gastric cancer. All the serial sections of the surgically resected specimens have not found cancer. It may be that the biopsy forceps cut off the cancer and the hemorrhage and mechanical damage during biopsy, so that the residual cancer tissue remains. Shedding, 16 cases have been officially reported in China, and have been reported abroad.

(4) Metastasis of early gastric cancer: the most common is lymph node metastasis, about 5% of intramucosal cancer, about 25% of submucosal cancer, and local lymph node metastasis. In addition to lymph node metastasis, there may be organ metastases, most commonly found in the liver, accounting for only 0.5% of all cancers. This type of early cancer invasion depth as much as submucosal, mostly bulging type, mostly differentiated, often with vascular tumor thrombus and lymph node metastasis.

4. Progressive gastric cancer When the infiltration of cancerous tissue reaches the muscular layer, the serosal layer or serosal outside is called advanced gagtric cancer, also known as advanced gastric cancer.

(1) General classification: Borrmann (1926) classified advanced gastric cancer into polyp type (type I), ulcer type (type II), infiltrating ulcer type (type III), and diffuse infiltrating type (type IV).

Type I: polypoid. The tumor mainly grows into the gastric cavity, the bulge is obvious, it is polypoid, the base is wider, the boundary is clearer, the ulcer is rare, but there may be small erosion. This is the least common type of advanced gastric cancer, accounting for about 3% to 5%.

Type II: limited ulcer type. The tumor has a large ulcer formation, the edge bulge is obvious, the boundary is clear, and the infiltration into the surrounding is not obvious. This type accounts for about 30% to 40%.

Type III: infiltrating ulcer type. The tumor has a large ulcer formation, and its edge is partially bulged, partially infiltrated and destroyed, the boundary is unclear, and the infiltration into the surrounding area is more obvious. The infiltration of the cancer tissue under the mucosa exceeds the tumor boundary seen by the naked eye. This is the most common type, accounting for about half.

Type IV: diffuse infiltration. It is diffusely infiltrated and it is difficult to determine the tumor boundary when touched. Due to the diffuse infiltration of cancer cells and fibrous tissue hyperplasia, the stomach wall can be thickened and stiffened, that is, the so-called "bag stomach", if the tumor is confined to the antrum. Then an extreme ring narrowing is formed. This type accounts for about 10%.

(2) Histological classification:

Common type: papillary adenocarcinoma, which forms a nipple structure. Tubular adenocarcinomas, which constitute glandular or glandular cavities of varying sizes, including highly differentiated and moderately differentiated adenocarcinomas. In poorly differentiated adenocarcinoma, most of the cancer cells do not form obvious lumens, which are strips or clumps, with nuclear eccentricity, and cytoplasm may contain mucus. Mucinous adenocarcinoma cells produce a large amount of mucus, and the dilated glands are filled with mucus, also known as mucinous carcinoma. Mucinous cell carcinoma, also known as signet ring cell carcinoma.

Special types: Undifferentiated carcinomas of this type are common, with high malignancy and no adenoid structure. Others include squamous cell carcinoma, adenosual carcinoma (adenosquamous carcinoma), carcinoid, and mixed cancer.

According to the malignant degree of gastric cancer, it is divided into 4 grades: the first stage has obvious cell differentiation, the second and third grades are moderate, the fourth grade is the worst, and the degree of malignancy is high.

(3) Transfer method:

1 direct infiltration spread: direct infiltration spread is related to the location of gastric cancer, gastric cardia cancer often invades the esophagus, liver and omentum. Gastric cancer is mainly composed of omentum, liver and pancreas. The main mode of spread is that cancer cells infiltrated under the subserosal membrane spread across the pyloric ring or submucosal cancer cells through the lymphatic vessels, and rarely spread directly along the mucosa. Proximal cancer is different and can directly extend to the lower end of the esophagus.

2 lymph node metastasis: according to the distance from the cancer, divided into the first, second and third stations and distant lymph nodes, the first station is the lymph nodes near the cancer such as stomach size bend, pyloric up and down, side of the cardia, spleen. The second station was the spleen, liver, left gastric artery, and pancreaticoduodenal lymph nodes. The third station is adjacent to the celiac artery, the hilar, the mesenteric aorta, and the lymph nodes around the middle colon. Distal lymph node mediastinum and left supraclavicular fossa or bilateral supraclavicular lymph nodes (Virehow lymph nodes).

Lymph node metastasis: generally from near to far, through the lymphatic spread widely spread, mostly diffuse gastric cancer. The transfer of cancer cells through the thoracic duct to the right supraclavicular lymph node is sometimes the first symptom and sign of clinical appearance. In some cases, the reason for the so-called "jumping" metastasis is related to the change of lymphatic flow in gastric cancer. Tumor growth and dissemination can cause tumor blockage of some lymphatic vessels, while other lymphatic vessels are re-formed. Insufficient amount of lymph fluid outflow in the stomach, so cancer cells can not only spread along the local lymphatics, but also spread along the lymphatic vessels that are constantly open, forming distant lymph node metastasis.

3 blood transfer: advanced patients can account for 64%, in the transfer of various organs, the most common liver accounted for 40%, lung accounted for 30%, followed by pancreas, adrenal gland, bone, kidney, spleen, brain, skin and so on.

4 planting metastasis: the cancer cells are soaked in the serosa, the planting in the peritoneum forms many metastatic nodules, producing a large amount of ascites, which can be transferred to the rectum.

Examine

an examination

Related inspection

Gastrointestinal dysfunction gastrointestinal CT examination

Sign

There was no positive sign in the abdominal examination of early gastric cancer, so the examination did not help early diagnosis. When entering the advanced stage (intermediate and advanced stage), there may be tenderness in the upper abdomen, fullness or mass in the stomach area, hard and fixed, and the surface is uneven and nodular. When the pyloric cancer is obstructed, the dilated stomach type can be seen, and there is a water sound, and the upper abdomen is full. Invasion of the pancreas, especially the invasion of the head of the pancreas and the duodenal ligament of the liver and the duodenum, the lymph node metastasis of the pancreaticoduodenal compression of the common bile duct, obstructive jaundice. When there is intrahepatic metastasis, the surface of the liver is uneven and hard, and may also be accompanied by jaundice. Peritoneal implantation can produce ascites, mostly bloody. Intestinal obstruction can occur in the small intestine, colon and mesenteric metastases, and intestinal and peristaltic waves appear. The female patient is transferred to the ovary and is a Krukenberg tumor. Distal lymph node metastasis may occur on the left supraclavicular or bilateral supraclavicular lymph nodes. These signs indicate that they have entered the middle and late stages, and many have lost the opportunity to cure the disease.

If you pay attention to the common pathogenesis and clinical features of the elderly, early diagnosis can be obtained in most cases. Patients should be further examined for the following situations, and if necessary, they should be observed regularly and repeatedly.

1. Anyone over the age of 60 who has a history of chronic gastritis and has been confirmed as atrophic gastritis or has obvious intestinal metaplasia, confirmed chronic gastric ulcer, gastric adenomatous polyp, or has undergone subtotal resection of the stomach has 5 ~ For more than 10 years, all should be the key monitoring targets, regular barium meal examination, cytological examination, or gastric fiber endoscopy.

2. There are general gastrointestinal symptoms, even if the symptoms are mild, such as continuous or intermittent episodes for 3 to 6 months or more.

3. Have a history of ulcers, such as regular changes in symptoms, or frequent episodes.

4. Unexplained weight loss, or long-term fecal occult blood test positive.

Diagnosis

Differential diagnosis

Differential diagnosis of gastric mass:

1, the upper abdomen mass: upper abdomen lesions caused by various reasons, palpation has a mass. Common in liver cirrhosis, chronic pancreatitis, stomach cancer, gallbladder cancer and other diseases.

2, upper abdominal cystic mass: abdominal mass refers to the abnormal mass that can be touched during abdominal examination. Common causes include swelling of organs, swelling of hollow organs, tissue hyperplasia, inflammatory adhesions, and benign and malignant tumors. Upper abdominal cystic mass is the main sign of clinical manifestations of hepatic hydatid cysts. The clinical manifestations are not obvious, more common in young and middle-aged, initial asymptomatic, with cyst enlargement and upper abdominal mass, abdominal distension, abdominal pain, such as located in the right upper liver, showing diaphragmatic elevation, may have respiratory symptoms. Many patients have had allergic reactions. A small number of jaundice can be produced by cystic compression of the biliary tract. There are also complication of infection or cholangitis or septicemia. Respiratory symptoms or bronchial biliary fistula can occur in the chest. The main signs are upper abdominal cystic masses, and those located above the swelling only see hepatomegaly. Corresponding signs may appear in patients with complications.

3, left upper abdominal mass with hematemesis, black stool: left upper abdominal mass with hematemesis, black stool is one of the clinical manifestations of gastric teratoma.

4, the left lower abdomen can touch the tender mass: the lower left abdomen can touch the tender mass block can be seen in ulcerative colitis, rectum, sigmoid cancer. Rectal, sigmoid schistosomiasis granuloma, left ovarian cyst and so on.

5, abdominal mass: abdominal mass refers to the abnormal mass that can be touched during abdominal examination. Common causes include swelling of organs, swelling of hollow organs, tissue hyperplasia, inflammatory adhesions, and benign and malignant tumors.

6, the abdomen can touch a huge soft mass: the giant bladder - small colon - intestinal peristalsis syndrome patients are still normal weight at birth, later abdominal bloating, no meconium, the abdomen can touch a huge soft mass, often susceptible to urinary Is an infection.

7, abdomen "gas-like" mass: abdominal "gas-like" mass is a symptom of colon cancer. Colon cancer is more common in middle-aged and elderly people, and the majority of men aged 30-69 are more than women. Early symptoms are not obvious. Symptoms of common symptoms in the middle and late stage include abdominal pain and gastrointestinal irritation, abdominal mass, bowel habits and fecal trait changes, symptoms caused by anemia and chronic toxin absorption, and intestinal perforation.