Gastric leiomyosarcoma

Introduction to gastric leiomyosarcoma Leiomyosarcomaofstomach is a malignant tumor originating from gastric smooth muscle tissue. It is the second most common non-Hodgkin's lymphoma in gastric non-epithelial malignancies. Its clinical manifestations include X-ray barium meal and gastroscopy. Lack of specificity, easy to be confused with gastric cancer, gastric leiomyoma and other primary gastric tumors, preoperative diagnosis and differential diagnosis are more difficult. Clinically, gastric leiomyosarcoma is not easy to completely remove, and the chemotherapy effect is not good, and the prognosis is poor. Gastric leiomyosarcoma occurs mostly from the muscularis of the stomach. It is rare, accounting for only 20% of the intragastric tumors. The gender difference is small, and the average age is 54 years. basic knowledge The proportion of illness: 0.005% Susceptible people: good for the elderly Mode of infection: non-infectious Complications: upper gastrointestinal bleeding

Causes of gastric leiomyosarcoma

(1) Causes of the disease

Similar to other stromal tumors in the gastrointestinal tract, gastric leiomyosarcoma mainly originates from smooth muscle tissue, and a small part may be of neural origin, and some of it is malignant from benign gastric leiomyomas.

(two) pathogenesis

Most of the gastric leiomyosarcoma is located in the proximal 1/2 of the stomach, that is, the cardia, the fundus area, followed by the stomach, and the giant leiomyosarcoma sometimes affects the entire stomach.

1. Gross tumors vary in size and can be single or multiple, ranging from a few millimeters to more than ten centimeters, or even more than 20 centimeters. Generally, the diameter is about 10 cm, which is nodular or lobulated, and smaller leiomyosarcoma is located. In the stomach wall, the appearance is similar to that of leiomyomas. It can be broadened to no pedicle in the stomach cavity, and a few can be pedicle-like. The gastric mucosa on the surface often has ulceration, small and superficial, about 0.2cm in diameter, large. Up to 5cm or more, larger tumors often protrude out of the stomach cavity, a few are dumbbell-shaped, and can invade surrounding organs and tissues. It is generally believed that the tumor is nodular, grows into the cavity or outside the cavity, and has a capsule. Sexual or large irregular ulcers, mostly leiomyosarcoma, cut surface is light brown or yellowish white, after the formalin fixation is pale brown red, visible braided fiber bundles, and necrosis, hemorrhage and sac Sexual change.

The tumor is spherical or hemispherical, mainly spreads under the mucosa, and grows perpendicularly to the stomach wall. It can be single or multiple, and some of it is malignant from benign leiomyomas. It occurs in the middle and upper part of the stomach wall to the stomach. More common, followed by the bottom of the stomach.

Half of the cases have central tumor ulcers, and the blood circulation is rich. Therefore, upper gastrointestinal bleeding is often prone to occur after rupture. The tumor can directly invade the surrounding tissues of the stomach, often involving the greater omentum and retroperitoneum, and metastasized by blood, more common in the liver. Second, the lungs, lymphatic metastasis is not common.

2. Histological characteristics Tumor cells are fusiform, similar to normal smooth muscle, rich in cytoplasm, central nucleus, oval or rod-shaped, stained plasmid thick, visible nucleoli, but the number of tumor cells is dense and dense. Obviously shaped, the nucleus is pleomorphic, the nucleus is huge and densely stained or the shape and shape are different. The nucleolus is thick, and the multinucleated giant cells are visible. The mitotic figures are more common. The tumor cells are bundled and woven, and the tumor stroma is less. There are glassy changes and mucous degeneration. Tumor cells are sometimes arranged in a grid shape, which is similar to schwannomas.

The difference between leiomyosarcoma and benign leiomyomas is that the size of the tumor is difficult to judge as its benign and malignant. It is histologically identified mainly based on the heteromorphism of the cells and the number of mitotic divisions. Usually, the density of the cells is large without division. Tumors with few mitotic figures are called leiomyomas. On the contrary, tumors that are active and pluripotent are called leiomyosarcoma.

Martin discovered a subtype of gastric leiomyosarcoma in 1960 and called it leiomyoblastoma. In 1969, the World Health Organization recommended it to be called epidermoid leiomyosarcoma. Its histological feature is: the cell is round. Shape or polygon, no smooth muscle fiber, vacuole formation in the cytoplasm, so there is a translucent band around the nucleus, and the tumor cells gather in a sheet shape instead of a bundle or a braid. These two kinds of smooth muscle malignant tumors are not only histology, Its general morphology, biological behavior, clinical manifestations and prognosis are very similar.

Shiu et al. subdivided leiomyosarcoma and epidermoid leiomyosarcoma into two types, high malignant and low malignant, according to the morphological criteria of soft tissue sarcoma (Table 1). This pathological grade can accurately reflect the prognosis of patients.

3. Classification can be divided according to the location of the tumor:

(1) Intragastric type (mucosal type): The tumor is located under the mucosa and grows into the gastric cavity.

(2) Gastric type (subserosal type): The tumor is located under the serosa to grow outside the stomach.

(3) Stomach wall type (dumbbell shape): The tumor grows simultaneously to the submucosa and the subserosal, forming a dumbbell-shaped tumor with a tumor tissue connection in between.

4. The way the tumor spreads

(1) Hematogenous metastasis: Gastric leiomyosarcoma is mainly caused by blood transfer, and the metastatic site is more common in the liver, followed by the lung and brain.

(2) direct diffusion: can also be planted and disseminated, the subserosal cancer tissue can be directly spread to adjacent tissues and organs.

(3) Planting and metastasis: After the cancer cells break through the serosa, they can be planted on the peritoneum of the abdominal cavity and pelvic organs.

(4) Lymphatic metastasis: Lymphatic metastasis is less common.

Gastric leiomyosarcoma prevention

Because the cause of gastric cancer is not clear, there is no special precautionary method. In addition to diet hygiene, avoid or reduce the intake of possible carcinogens, you can eat more vegetables and fruits rich in vitamin C. For so-called precancerous lesions, Close follow-up, early detection of changes, timely treatment.

Gastric leiomyosarcoma complications Complications upper gastrointestinal bleeding

Half of the cases have central tumor ulcers, and the blood circulation is rich. Therefore, upper gastrointestinal bleeding is often prone to occur after rupture. It is more common in melena. A small number of patients may have vomiting coffee or red bloody stools when the amount of bleeding is large. Direct invasion of the surrounding tissues of the stomach, often involving the greater omentum and retroperitoneal, and metastasis through the blood, more common in the liver, followed by the lungs, lymphatic metastasis is not common.

Symptoms of leiomyosarcoma of the stomach Common symptoms Upper gastrointestinal hemorrhage, hard tumor cell infiltration, repeated bleeding, abdominal pain, nausea, abdominal discomfort, black stool, shock, ulceration

Symptoms are non-specific, depending on the location, size, growth rate and presence or absence of ulcers. About half of the patients are treated for upper gastrointestinal bleeding, followed by upper abdominal discomfort and mild pain, about 1/ 3 patients can lick the upper abdominal mass.

Upper abdominal discomfort, pain, upper gastrointestinal bleeding, mass is the main clinical manifestation of gastric leiomyosarcoma. Patients with gastric leiomyosarcoma have varying lengths of disease, time and extent of symptoms and tumor growth site, growth rate, type, disease period and There are factors such as ulcer bleeding, etc. In the early stage, the tumor tends to grow outside the cavity, the symptoms are concealed, and there is no special clinical manifestation. As the tumor progresses, the typical performance is as follows.

1. Abdominal pain occurs in patients with upper abdominal discomfort of more than 50%, often preceded by bleeding and lumps, mostly dull pain, dull or burning pain, or abdominal discomfort, lasting more than 10 minutes to several hours, and some postprandial relief , often accompanied by pantothenic acid, loss of appetite, nausea and vomiting, occasionally severe pain, rupture of extraluminal mass caused by intra-abdominal hemorrhage or tumor perforation caused acute peritonitis, can be manifested as acute abdominal pain and abdominal periplasmic irritation, abdominal pain It is caused by swelling, pulling and pressing adjacent tissues.

2. About half of the patients with abdominal masses should check their body or lick their upper abdomen and abdomen. The smaller ones are like walnuts. The older ones are larger than the adult heads. They are more sticky, more fixed, generally harder, and some are sexy. The edges are clear, the tenderness is not obvious, and there may be tenderness.

3. Upper gastrointestinal bleeding, gastric leiomyosarcoma, gastric hemorrhage is also more common, often intermittent, persistent small amount of bleeding, mainly black stools, a small amount of bleeding can occur vomiting coffee-like or red bloody stools, Most patients with gastrointestinal bleeding as the first symptom of the treatment, very large bleeding or even shock, the main cause of bleeding is tumor compression or insufficient blood supply to the central site infarction, necrosis, and tumor surface ulcers, long-term repeated bleeding, can Symptoms and signs of obvious anemia are easily misdiagnosed.

4. Fever, weight loss In addition, like other malignant tumors, there may be irregular fever, weight loss, cachexia and other symptoms and signs.

Examination of gastric leiomyosarcoma

Laboratory inspection

1. Blood routine can have changes such as iron deficiency anemia.

2. Histopathological examination For suspected cases, routine biopsy should be performed during gastroscopy to confirm the pathological diagnosis. The biopsy should be taken deep, because the pathological changes of gastric leiomyosarcoma are mainly under the mucosa, and only 25% of the common biopsy forceps can reach the submucosal layer. Therefore, relying solely on endoscopic biopsy is unreliable. However, if a biopsy with a tumor at the top of the tumor is used, or a burrowing biopsy is used, multiple materials may be helpful for histological diagnosis. The positive rate is up to 53.8%. The diagnostic criteria are: 1 Tumor cell mitotic rate 4 / 25HPF; 2 tumor cells dense, obvious atypia; 3 tumor diameter 6cm; 4 tumor cells invade surrounding tissues; 5 necrosis and cystic changes.

Film degree exam

The diagnosis of gastric leiomyosarcoma mainly depends on x-ray barium angiography and gastroscopy or CT examination.

1. X-ray examination of gastric leiomyosarcoma in the general morphology of the extraluminal type and endoluminal type, X-ray barium meal has the corresponding characteristics.

(1) Intragastric type:

1 The round or semi-circular filling defect is visible under the mucosa, the edge is smooth, and the adjacent mucous membrane is soft.

2 The mucosal folds on the surface of the tumor disappeared, and the mucosal folds can reach the vicinity of the mass and creep to the edge of the tumor.

3 The tumor base is wider.

4 Individual cases see ulcers of varying sizes.

(2) stomach type;

1 When the mass grows to the outside of the cavity, the contour of the stomach is deformed and displaced by the external pressure, and the filling defect or shadow is formed.

2 If there is a large mass outside the stomach and the shadow coexist, this type should be considered, because there are few extragastric masses in gastric cancer.

(3) Stomach wall type: The tumor grows into the cavity at the same time, and it is connected to the inner and outer masses in a dumbbell shape.

(4) leiomyosarcoma at the bottom of the stomach: a semi-arc soft tissue mass is seen in the gastric vesicle, and the lower end of the esophagus is rarely involved even if the lesion is close to the cardia.

Barium angiography: The image features: a rounded filling defect with a neat edge in the stomach. Sometimes a typical umbilical ulcer can appear in the middle of the filling defect. If the tumor is a stomach type, the stomach is compressed and displaced. It is necessary to pay attention to observe whether the gastric mucosa is leveled or not, which is helpful for diagnosis (Fig. 3, 4).

1 soft tissue block or filling defect in the stomach: double contrast of gastric qi sputum can show a round, oval soft tissue mass, the contour is smooth, can be lobulated, the larger the lumps, the more obvious the lobes, the appropriate filling of the filling agent After that, the filling defect can be displayed. If the tumor is located on the small curved or large curved side of the corpus, the semi-curved filling defect appears on the tangent line, the contour is not regular, and the edge is not smooth.

2 gastric mucosal changes and sputum formation: tumor surface mucosa is easily damaged, combined with tumor necrosis, liquefaction, shedding, ulceration, X-ray barium meal contrast, tincture can enter the necrotic cavity, forming an irregular border shadow or " Bull's eye.

3 organ pushing displacement: When the extraluminal tumor volume is large, the gastric cavity can be deformed, and the surrounding organs can be displaced. The artificial gastro-abdominal wall angiography can clearly show the soft tissue mass of the local stomach wall and the size of the mass. , outline and range.

(2) CT, MRI examination: CT examination helps to determine the location, extent and extent of involvement of adjacent tissues or organs (Figure 5).

CT, MRI images and leiomyomas are difficult to identify, and the following characteristics are common:

1 soft tissue mass is usually very large, limited to one side of the stomach, the tumor surface is smooth or lobulated, the tumor grows into the cavity or outside the cavity, or simultaneously protrudes into the cavity, externally, typically dumbbell-like.

2 Occasionally, calcification is visible in the tumor on the plain scan.

3 necrosis and ulcer formation, soft tissue block see the low-density area, if you communicate with the stomach cavity, see the gas and contrast agent shadow, see the specificity.

4 Enhanced scanning In most cases, tumor enhancement was significant.

5 The tumor is clearly separated from the surrounding normal stomach wall.

6 The probability of liver metastasis is high, and lymph node metastasis is rare. In some cases, intrahepatic metastases show target heart sign, that is, a slight height is visible in the center of low-density lesions.

2. Gastroscopic examination shows the characteristics of submucosal mass: the mucosa on the surface of the tumor is translucent, and umbilical ulcer can appear in the center. If the tumor is large, the bridge wrinkles around the tumor are not as obvious as benign leiomyomas, and the boundary of the mass is unclear. , there are thick wrinkles and even the stomach wall is stiff.

The intraluminal or intracavitary type can be seen as a large and soft mass protruding into the stomach cavity. It is spherical, nodular or lobulated, with a smooth surface and ulcer or hemorrhage. The diameter of the tumor is more than 5cm. The pleats are limited to a part of the periphery of the tumor. In the inter-wall type, multiple nodules are formed under the mucosa, some of the folds disappear, and the surface mucosa is translucent, which may be accompanied by erosion, ulceration or bleeding.

In the gastroscopy biopsy, because the tumor is mostly located under the mucosa, deep excavation should be performed in the deep part of the mucosa to obtain a higher positive diagnosis rate. However, elderly patients need to be alert to the occurrence of major bleeding after deep biopsy.

3. Selective angiography leiomyosarcoma is a blood-rich tumor. Selective celiac angiography can detect tumor blood vessels, tumor staining, blood supply artery, etc. During the bleeding period, the contrast agent leaks into the ulcer surface and the gastric cavity. Provide a reference for the surgical approach, because it is an invasive examination, clinically less applied.

4.B-ultrasound for large-volume gastric leiomyosarcoma, B-ultrasound and CT examination are helpful for diagnosis. Most of the leiomyosarcoma with B-ultrasound examination have different levels of internal high and low echo zones, uneven echo and irregular shape. The edges are not clear, and sometimes liquefaction, necrosis, and cystic changes are visible, but the final diagnosis still requires histopathological examination.

5. Endoscopic ultrasonography Because the ultrasound endoscopic ultrasound frequency is high, it is in direct contact with the inner wall of the digestive tract, and the attenuation is reduced, so the resolution is high, which has a very high diagnostic value for identifying submucosal tumors and extra-wall compression. It shows the five-layer structure of gastric mucosa, which can identify submucosal lesions, extraluminal compression and depth of tumor infiltration. It has great diagnostic value for inter-wall type and mixed type, and provides help for clinicians to choose treatment options, leiomyosarcoma. Occurred in the muscular layer, the tomographic image often shows hypoechoic images in the muscular layer, the echo is uneven or uniform, and the edge is irregular. It needs to be judged according to the size of the tumor and the echo. For the tumor with diameter > 4.0cm, uneven echo, leiomyomas The possibility is extremely high. Ultrasound gastroscopy has important reference value for tumor size, growth pattern or depth of invasion and lymph node metastasis. It provides clues for improving the positive rate of biopsy, determining the surgical method and prognosis.

6. Catheter exploration of deep biopsy under gastroscopy is the key to the diagnosis of this disease; in some cases, there is a clear abdominal mass, which requires a caesarean exploration to make a final diagnosis.

Diagnosis and differentiation of gastric leiomyosarcoma

diagnosis

X-ray barium meal examination showed that the stomach was semi-circular filling defect, the edge was neat, sometimes the umbilical ulcer was visible in the center; the stomach type showed gastric pressure, the gastric mucosa was intact, the fold was flattened, the gastroscope Check the characteristics of the submucosal mass. If there is an ulcer, it is easier to confirm the biopsy from there.

It must be distinguished from benign leiomyomas. It is generally considered that tumors with a diameter of more than 3 cm should be considered malignant. For example, if the biopsy sees cells as pleomorphic, nuclear fission is active and should be considered malignant.

For middle-aged and elderly patients, there is a long period of upper abdominal pain and discomfort. Upper gastrointestinal bleeding and abdominal mass should consider the possibility of this disease. Further examination is needed. The clinical manifestations of this disease are diverse and extremely atypical. , endoscopy, etc., comprehensive consideration; if necessary, laparotomy to assist in diagnosis.

1. Clinical manifestations.

2. Laboratory and other auxiliary inspections.

Differential diagnosis

1. Identification of leiomyosarcoma and cardia cancer at the base of the stomach:

(1) There is a soft tissue mass in the stomach cavity of the musculocutaneous musculature at the bottom of the stomach, which is the same as the cardia cancer;

(2) leiomyosarcoma at the bottom of the stomach rarely involves the esophagus even near the cardia, and the cardia cancer involves the lower end of the esophagus, which is the basis for the diagnosis of cardiac cancer.

2 The disease needs to be differentiated from gastric leiomyoma, gastric cancer, and other non-epithelial malignant tumors of the stomach. The latter can be identified by pathological examination. The identification with the former is shown in Table 2. The diameter of leiomyomas is generally less than 3 cm, which is more limited. Round, more complete mucosa, rare bleeding and weight loss, biopsy, no pleomorphic cells, no giant cells, few mitotic divisions, if the tumor is more than 3cm in diameter, accompanied by ulcers and hemorrhage, weight loss, histology Check the cells for pleomorphism, visible giant cells, active nuclear division, should be considered leiomyosarcoma.

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