Wasting weight loss is a manifestation of weight loss due to wasting diseases, which can be seen in tuberculosis, diabetes, hyperthyroidism, etc. Many diseases can cause wasting, the most common ones such as diabetes, hyperthyroidism, tumors, etc. The harm that wasting brings to us should not be ignored, there are also problems caused by heavy exercise, poor diet and sleep, excessive mental stress, pay attention to check the specific situation. Adenocarcinoma of the small intestine is a common cause of wasting weight loss. Adenocarcinoma of the small intestine is a malignant tumor from the mucosa of the small intestine, mostly located around the papilla of the duodenum, jejunum and ileum. It is one of the most common primary malignant tumors of the small intestine. Among small bowel adenocarcinomas, those occurring in the duodenum tend to have early symptoms and are easy to diagnose and treat. The clinical manifestations of adenocarcinoma of small intestine are mostly related to the location of the tumor. The common manifestations include abdominal pain, gastrointestinal bleeding, intestinal obstruction, weight loss, nausea, vomiting, anemia, and fever. Jaundice is also seen in duodenal adenocarcinoma. Abdominal masses are rare. The diagnostic criteria are as follows: 1. Abdominal pain: usually chronic abdominal pain, not closely related to diet. The pain is mostly in the middle or right side of the upper abdomen, with persistent dull pain, distension and vague pain, and gradually worsens, resulting in loss of appetite, emaciation and weakness. The abdominal pain is severe when intestinal obstruction or intestinal perforation occurs. 2, obstructive symptoms: often one of the main reasons for patients to visit the clinic, ring stenosis lesions are often chronic incomplete intestinal obstruction as the main manifestation, the mass is infiltrative growth, so that the intestinal cavity stiff, narrow, intestinal obstruction. Patients often have vomiting, abdominal distension, and vomit is stomach contents with bile or blood. 3.Gastrointestinal bleeding: More common, ulcerated adenocarcinoma surface may show paroxysmal or continuous gastrointestinal bleeding due to vascular erosion and rupture. If the lesion involves larger blood vessels, there may be a lot of bleeding, which may appear as vomiting blood or blood in stool, black stool or dark red stool, or even hypovolemic shock. Long-term chronic blood loss is associated with anemia. 4.Abdominal mass: The size of small intestine adenocarcinoma is usually small and rarely appears as a mass, but in about 1/3 of patients, an abdominal mass can be found at the time of consultation, which may be an obstructed proximal dilated and thickened intestine. The mass can sometimes be found in those who grow outside the lumen, and there may be pressure pain, and the mass is clearly defined in those who are emaciated. 5.Jaundice: 80% of the descending duodenal tumors have jaundice as the main symptom. Obstructive jaundice occurs when the mass compresses the common bile duct or duodenal papilla and causes bile duct obstruction. In the early stage, the jaundice is fluctuating, but in the later stage, it is persistent and gradually deepens. 6.Signs: Patients may show emaciation, anemia, abdominal pressure pain, the site of pressure pain is often the site of the mass, to the late stage of the abdominal mass can be palpated. In case of intestinal obstruction, there are intestinal pattern and peristaltic waves, and hyperactive bowel sounds. In cases of intestinal perforation, there may be signs of peritoneal irritation. In cases with liver metastases, an enlarged liver may sometimes be palpable.