It refers to the masses of internal and external organs and tissues in the abdominal cavity caused by various reasons. The cystic inflammatory masses in the left upper abdomen with obvious pressure pain, such as the masses in the middle of the upper abdomen are often tumors, cysts or stones in the stomach or pancreas. If there is a cystic mass with pressure pain in the left upper abdomen, the following diseases should be considered: 1. Gastric cancer Mostly seen in middle-aged male patients, clinical manifestations are wasting, epigastric pain and discomfort, upper gastrointestinal bleeding, etc. When there is an abdominal mass, it indicates that the lesion is advanced, the mass is mostly located in the upper abdomen or above the umbilicus, with hard texture, irregular surface and unclear boundary, and the advanced stage can be complicated by pyloric obstruction. The diagnosis can be made by barium X-ray or gastroscopy and biopsy. 2. Pancreatic pseudocysts are mostly secondary to pancreatitis or trauma to the pancreas. The abdominal masses are mostly located in the upper and middle abdomen, varying in size, round or oval, with a smooth surface; if the pseudocyst compresses the lower part of the common bile duct, persistent or slowly deepening jaundice may occur; ultrasound and CT examinations may reveal cystic masses of the pancreas.