What are the pathological changes of gastric cancer?

(A) the occurrence of gastric cancer site
     Gastric cancer can occur at any part of the stomach, more than half occurred in the gastric antrum, stomach lesser curvature and anterior and posterior wall, followed by the cardia, gastric body area is relatively small.

     (B) the giant sub-type body morphology
     1. Early gastric cancer regardless of the size range of the early lesion limited to mucosa and submucosa. Can be divided into protruded type (polypoid type), superficial type (gastritis type) and depression type (ulcer type) III. In another sub-type Ⅱ Ⅱ a (superficial elevated type), Ⅱ b (superficial flat type) and Ⅱ c (superficial depressed type) 3 subtype. Of the above types may have different combinations. If Ⅱ c + Ⅱ a, Ⅱ c + Ⅲ, etc. (Figure 1). Early gastric cancer in the 5 ~ 10mm in diameter are called small stomach, diameter <5mm, said a small gastric cancer.

     2. The progress of advanced gastric cancer, also known as gastric cancer, cancer diseases and muscular invasion or full-thickness, often shift. There are several types (Figure 2):
     (1) mushroom umbrella (or polypoid type): advanced gastric cancer accounts for about 1 / 4, cancer limited, mainly to the cavity growth, was nodular, polypoid, rough surface, such as cauliflower, the Central Authorities have erosion, ulcer , also known as nodular fungating type (color Figure 3). Cancer was discoid, marginal high, the central ulcers were called discoid mushroom umbrella.

     The posterior wall of gastric antrum lesser curvature with a prominent stomach tumor cavity, slightly lobulated, the surface uneven granular, and see there is erosion. Tumor base is slightly small, was iati type, no significant infiltration of the surrounding mucosa

     (2), ulcer type: advanced gastric cancer accounts for about 1 / 4. Is divided into restricted ulcer type and infiltrating ulcer type, the former is characterized by cancer limitations, was discoid, central necrosis. Are often larger and deeper ulcers; ulcer at the end of the general grievance, marginal uplift was dike-like or crater-like, the cancer to the deep infiltration, often accompanied by bleeding, perforation. Ulcer type is characterized by infiltrating cancer was invasive growth, often sharp and deep infiltration surrounding the tumor, central necrosis of the formation of ulcers, often earlier, and serosal invasion or lymph node metastasis.

     (3) infiltrating type: This type is also divided into two kinds, one for the limitations of infiltrative type, infiltration of gastric cancer tissue layers, mostly limited to the gastric antrum, infiltration of the gastric wall thickening and hardening, folds disappear, multi no obvious ulcer and nodules. Infiltration confined to the stomach part of the persons, referred to as "limited infiltrating." The other is diffuse infiltrative type, also known as leather stomach cancer in the submucosal expansion, invasion, and floors, a wide range, so that the stomach cavity smaller, thick gastric wall stiffness, mucosal still exist, may have congestion and edema without ulcers.

     (4) Mixed type: the same time, the coexistence of the above types of two or more lesions.

     (5) Multiple cancer: cancer was multifocal, with each other. Such as atrophic gastritis based on the occurrence of gastric cancer that may belong to this type, and more in the upper gastric body.

     (C) the histological type
     According to the organizational structure can be divided into four types.
     ① adenocarcinoma: including papillary adenocarcinoma, tubular adenocarcinoma and mucinous adenocarcinoma, according to their degree of differentiation into well-differentiated, moderately differentiated and poorly differentiated three kinds;
     ② undifferentiated carcinoma;
     ③ mucinous carcinoma (ie, signet-ring cell carcinoma);
     ④ special type of cancer: including adeno-squamous cell carcinoma, squamous cell carcinoma, carcinoid and so on.
     Took place in accordance with the organization can be divided into two types. ① intestinal type: cancer originated in the intestinal gland metaplasia of the epithelium and well differentiated carcinoma, giant body morphology mostly fungating; ② gastric type: cancer originated in the gastric mucosa inherent, including undifferentiated carcinoma and mucinous carcinoma, carcinoma differentiation poor, mostly giant ulcer-type body morphology and diffuse infiltrating type.

     (D) transfer means
     1. Direct disseminated invasive gastric mucosa or serosa may be along directly to the stomach, the esophagus or the duodenum develop. Once the cancer invasion and serosa, that is, easier to adjacent organs or tissue, such as the surrounding liver, pancreas, spleen, transverse colon, jejunum, diaphragm, omentum and abdominal wall infiltration and so on. Off when cultivable cells in the abdominal cavity, pelvis, ovary, bladder and rectum, etc. lacuna.

     2. Lymph node metastasis of gastric cancer metastasis accounted for 70% of the lower stomach cancer often transferred to the pylorus, the stomach and so on, under and beside the celiac artery lymph nodes, while the upper part of pancreatic cancer often transferred to the next cardiac beside the upper gastric lymph nodes. With advanced cancer may be transferred to the aorta and the diaphragm on the surrounding lymph nodes. As the intra-abdominal lymph nodes and thoracic duct direct traffic, they can be transferred to the left supraclavicular lymph nodes.

     3. Hematogenous metastasis in some patients can be found in peripheral blood of cancer cells can be transferred to the liver through the portal vein and reach the lung, bone, kidney, brain, meninges, spleen, skin, etc..