A lump in the stomach when felt indicates a mass in the abdominal cavity, which needs to be examined in a timely manner to avoid delaying the condition and causing the mass to increase in size. A mass in the abdominal cavity occurs in more common locations, such as the stomach, small intestine and colon. If masses are found in stomach, it usually indicates gastric mesenchymal tumor or gastric cancer; if masses are found in small intestine, it usually indicates more small intestine mesenchymal tumor; if masses are found in colon, it usually indicates colon cancer, which requires abdominal CT examination and gastroscopy or colonoscopy if necessary. The advantage of gastroscopy is that the location of the lesion can be found visually and pathology can be taken for laboratory tests. If the pathology confirms a malignant tumor, radical tumor surgery will be required. If the mass is benign, it is also necessary to perform a mass removal surgery, and after the removal, pathology is routinely sent for examination.