Generally speaking, a lump felt in the left abdomen may be a fecal mass, abdominal tumor, etc., and further examination is needed to confirm the diagnosis. 1. Stool lumps: when constipation or prolonged defecation is not smooth, it will cause feces to accumulate in the sigmoid colon of the left abdomen, forming a hard lump in the shape of a bar, which can be definitively diagnosed by history and ultrasonography. It is recommended to drink more water, eat more fresh vegetables and fruits, don’t eat cold, spicy and stimulating food, and keep the bowel movement smooth in daily life. 2. Abdominal tumor: sarcoma or intra-abdominal tumor can invade the abdominal wall and form a fixed position in the abdomen. Common malignant tumors in the left side of abdomen are descending colon cancer, and there may be pancreatic cancer, stomach cancer, subcutaneous lipoma, fibroma, left pelvic tumors, such as ovarian cancer, ovarian cysts, chocolate cysts, teratomas and so on. Additionally, disorders such as splenomegaly, left ectopic pregnancy, and sebaceous cysts in the left abdomen may also be palpable as a mass in the left abdomen. The presence of abdominal mass, need to do further abdominal CT, ultrasound and other examinations, if necessary, do colonoscopy to further clarify the diagnosis.