Metastatic small intestinal tumors

　　The primary tumor of small intestinal metastases can originate from cervical cancer, malignant melanoma, colorectal cancer, ovarian cancer, renal cancer, gastric cancer, lung cancer, and skin cancer, etc. Metastatic sites are often seen in the ileum, especially the distal ileum, followed by the jejunum, and the duodenum is less common. This disease can be single (such as adenocarcinoma) or multiple (such as malignant melanoma), and squamous cell carcinoma can be seen in both. The size of the metastatic site is 0.5-12 cm, with an average of 3-5 cm. The tumor invades the intestinal wall, with ulcerated surface and central necrosis leading to acute or chronic perforation, or due to stenosis, intussusception, torsion, adhesion, infiltration, etc., leading to intestinal obstruction. Regional lymph nodes are involved in 40%, and the histological classification is mostly adenocarcinoma and squamous cell carcinoma, followed by malignant melanoma.

　　The most common complication of patients with metastatic small intestinal tumors is intestinal obstruction. Initially, due to tumor infiltration of the intestinal tract or compression of the intestinal tract, it causes stenosis of the intestinal lumen, manifesting as chronic incomplete intestinal obstruction. On the basis of intestinal obstruction, it may further develop into intestinal perforation and peritonitis, and some patients may develop perforation due to necrosis, erosion, and infection of the tumor lesion.

　　The primary site of metastatic small intestinal tumor is often surgically resected or controlled by treatment, but it can also be hidden and discovered simultaneously with the metastatic site. The onset is often sudden, and clinical symptoms often present with partial intestinal obstruction, which may progress to complete intestinal obstruction. Acute cases are usually complete intestinal obstruction or perforation, subacute cases are often bleeding, and chronic cases are mostly partial intestinal obstruction. The specific manifestations are as follows.

　　1. Abdominal pain:It is the most common symptom, with about 80% of patients experiencing varying degrees of abdominal pain, which is one of the main reasons for seeking medical attention. Abdominal pain is usually located in the lower abdomen and around the umbilicus, and may also occur in the upper abdomen. The initial pain is often dull, hidden, or bloating, which worsens after meals and is often accompanied by intestinal rumbling. With the development of the lesion, in the late stage, due to the infiltration of the tumor into the intestinal tract to complete blockage, intussusception, intestinal torsion can lead to complete intestinal obstruction. Patients may experience persistent severe colic pain, exacerbation in paroxysms, and symptoms such as abdominal distension, nausea and vomiting, cessation of anal exhaust and defecation, often requiring emergency surgery to relieve obstruction.

　　2. Intestinal obstruction:It is one of the common complications, initially due to tumor infiltration of the intestinal tract or compression of the intestinal tract, causing intestinal stenosis, manifested as chronic incomplete intestinal obstruction. When the disease lasts for a long time, the patient can see the起伏of gastrointestinal shape and peristalsis wave, sometimes feel the mass in the abdomen moving up and down, and there is a feeling of gas moving.

　　3. Diarrhea:About 1/3 of patients have diarrhea symptoms, caused by intestinal stimulation or malabsorption due to extensive small bowel involvement. At the beginning of the disease, the stool is paste-like, 4 to 5 times a day, without obvious mucus and pus. With the progression of the disease, the frequency of stool increases, and mucus increases.

　　4. Hemorrhage:It is relatively common, generally manifested as positive occult blood in feces, only when there is a large amount of bleeding can black stool, tarry stool be seen. The cause of bleeding is mainly due to the erosion, ulceration, and necrosis of the tumor surface.

　　5. Abdominal mass:Clinically, about 1/3 of patients can palpate abdominal mass. The size is not uniform, the small ones have several centimeters, the large ones have more than ten centimeters, the shape is mostly irregular, has a nodular sensation, and mild tenderness. In the early stage of the disease, the mass can be moved, with the progression of the disease, the mobility gradually decreases, and finally becomes completely fixed.

　　6. Intestinal perforation and peritonitis:Mostly develop into intestinal perforation on the basis of intestinal obstruction, some are due to tumor necrosis, erosion, infection, and perforation. Acute perforation can cause diffuse peritonitis with extremely high mortality rate. Chronic ones may cause intestinal adhesion between loops, abscess, intestinal fistula, etc.

　　7. Other:Part of the cases may have fever, mostly low fever, high fever is rare, may have fatigue, anemia, loss of appetite, abdominal distension, weight loss and jaundice, etc. In the late stage, due to tumor consumption and diarrhea, the patient eats less and appears cachexia.

　　Metastatic sites are more common in the ileum, especially the distal ileum, followed by the jejunum, and the duodenum is less common. There is currently no effective preventive measure, early detection and early diagnosis are the key to the prevention and treatment of this disease.

　　The blood routine examination of metastatic small intestinal tumor can show anemia, blood sedimentation can be accelerated, occult blood in feces can be positive. In addition to laboratory tests, the auxiliary examinations commonly adopted for this disease are as follows.

　　One, X-ray examination: Abdominal X-ray can show gas-liquid level, abdominal plain film can also show soft tissue mass shadow. Double-contrast small bowel barium enema examination is of great value in detecting small bowel metastatic tumors, the specific performance is as follows.

　　1. Localized concentric stricture, mucosal destruction, villi disappearance, smooth and rigid intestinal wall.

　　2. Solitary prominent lesion, filling defect.

　　3. Ulcer formation, irregular large龛影, often accompanied by mild stricture and nodular lesions.

　　4. Formation of fistula, leakage of barium.

　　5. Frozen sign, seen in widespread abdominal metastases and malignant diffuse peritoneal mesothelioma.

　　6, multiple nodular intestinal wall indentation, visible with signs of intestinal obstruction, occasionally with pneumoperitoneum.

　　Second, ultrasound and CT: Ultrasound and CT are convenient for finding the size, location, infiltrative depth, and relationship with surrounding tissues of the tumor, and can find the primary focus. The tumor diameter greater than 2cm can be displayed. Oral contrast agent CT scan can show irregularities, destruction, indentation, and sinusoids in the intestinal lumen, and can clearly show extraintestinal metastasis foci and lymph node metastasis.

　　Third, selective mesenteric arterial angiography:This is very helpful for the diagnosis of metastatic tumors in the small intestine, and it has a high value for improving the detection rate and localization diagnosis of small intestinal metastatic tumors, especially for tumors with hemorrhage, the diagnostic value is greater. The literature reports that the positive rate of this method is >90%, and its specific performance is as follows.

　　1, the infiltration and displacement of the tumor into the blood vessels.

　　2, the formation of new blood vessels in the tumor.

　　3, the cystic change and necrotic area of the tumor are filled with contrast medium, showing 'lake', 'pool', or 'sinus' shape.

　　4, the tumor surrounds the narrowing and obstruction of the blood vessels.

　　5, the capillary perfusion time is prolonged or the permeability increases, and there is a shadow of tumor staining.

　　6, multiple nodular intestinal wall indentation, visible with signs of intestinal obstruction, occasionally with pneumoperitoneum.

　　Fourth, fiberoptic endoscopy: It is very helpful for the metastatic tumors in the duodenum, and the proximal jejunum can be chosen for enteroscopy, and the distal ileum can be examined by colonoscopy.

　　Fifth, laparoscopic examination: It can directly find the lesions inside the abdomen and can take biopsies for diagnosis, but it is an invasive examination with high cost, and it is rarely used in clinical practice.

　　Patients with metastatic small intestinal tumors should pay attention to eating high-fat and low-fiber foods in their diet. Patients should also avoid strong alcohol, spicy, hot, and stimulating foods. Eat less fried, smoked, and salted foods.

　　If the cancer in other parts of the body has metastasized to the small intestine, it indicates that the primary tumor is in the late stage and generally cannot be removed. If the metastasis site is solitary or relatively limited, resection and anastomosis of the diseased intestinal segment can be performed to maintain the patency of the gastrointestinal tract, relieve obstruction, but it is a palliative surgery. If the focus is extensive or the infiltrative range is large, a bypass operation or stoma operation can be performed. If necessary, chemotherapy or radiotherapy can be combined with pathological type, which can achieve certain therapeutic effects.