A fetus born with hydatid cystic aneurysm will present with a swelling in the neck that is fluctuating to the touch, which is a benign condition. Fetuses with hydatid cystic aneurysm are usually detected by ultrasound during pregnancy. The incidence of the condition is usually low and is an abnormality of the lymphatic tissue, which usually occurs in the neck of the fetus. When the fetus is born, there will be a cystic mass in the neck with a smooth surface and a relatively large sense of fluctuation, and when pressed, there will be no obvious tenderness, and the fluid in it will be lymphatic fluid. This is a benign disease. If a pregnant woman discovers the presence of hydatid cystic tumor in her fetus during a physical examination, it is recommended to seek timely medical treatment, consult the doctor about the specific situation and the treatment methods that need to be taken to promote the good physical development of the fetus.