Recently, our pediatric surgery department successfully performed a giant mesenteric cyst excision for a premature baby born at only 12 days old. The successful implementation of the operation marked a new level of pediatric surgery technology in the hospital. According to the report, the baby’s name is Doudou (a pseudonym), Doudou’s mother found that the baby had mesenteric cysts during an ultrasound examination in late pregnancy, and after consulting a pediatric surgeon, she learned that the cysts could be surgically removed after birth. On March 10, Doudou was born, weighing only 2400g at birth. The doctor found that Doudou’s little belly was much larger than normal and bulging, so she was referred to our pediatric surgery department. Referring to the ultrasound examination results during pregnancy and after further examination, the doctor made a detailed surgery plan for Doudou. On March 22, Doudou was pushed into the operating room, and the deputy director of pediatric surgery, Zhou Xuewu, led his assistant, Sha Yongliang, to perform surgery on Doudou. The operation was a complete success. According to the introduction of Zhou Xuewu, deputy director of pediatric surgery, mesenteric cyst is an abnormal development of mesenteric lymphatic vessels during embryonic life, and the lymphatic flow is obstructed, and the lymphatic fluid collects to form cysts, and the cysts keep increasing as the child grows and develops. Cysts can cause bleeding and infection, intestinal torsion and intestinal adhesions, leading to intestinal obstruction and even intestinal necrosis. Once the diagnosis is clear, surgery should be performed. Mesenteric cysts often have intact envelope, isolated cysts can be removed, if the cyst is closely adhered to the mesenteric vessels or involves the adjacent intestine, it can be removed together with part of the small intestine. At present, Doudou has been safely discharged from the hospital. The complication rate of pediatric mesenteric cysts is not high, and this kind of giant mesenteric cyst in this child is even rarer, as many children are diagnosed due to intestinal obstruction, and the prognosis of this disease is good after surgery as long as the resection is complete. Therefore, parents are reminded that if a fetal mesenteric cyst is detected during pregnancy, surgery should be performed promptly after birth, otherwise it may induce complications such as intestinal obstruction, intestinal necrosis and intestinal torsion, which can seriously affect the growth and development of the newborn.