In the past, the decision of either the fetal parents or the obstetrician was to induce labor and have another one, not only for lung masses, but also for masses anywhere in the fetus, because the nature of the mass was not known. However, all natural persons including newborns with benign tumors can be surgically removed to obtain a good prognosis, so why is the fetus deprived of this right to live? With the development of fetal medicine in the last two decades, the human rights of the fetus, a small patient, have become more and more important worldwide. At the same time, through intrauterine and extrauterine diagnosis and treatment of various masses in the fetus and long-term follow-up, we realized that many benign fetal masses are treatable and have a good long-term prognosis. Among them, benign fetal lung masses are more comprehensively recognized. Common benign fetal lung masses include congenital pulmonary cystadenoma and bronchopulmonary isolation, and less commonly, bronchogenic cysts, pericardial cysts, thymic cysts, and duplicated esophageal and neural tube prointestinal cysts. The diagnosis of all pulmonary masses is based primarily on ultrasonography. Most pulmonary masses appear as anechoic cystic masses on ultrasound, and some appear as parafirm masses. The most common congenital cystic adenoma of the lung (CCAM) is a multicystic mass of lung tissue consisting of hyperplastic bronchial structures, whereas bronchopulmonary segregation (BPS) is a mass of nonfunctional lung tissue with no apparent traffic to the bronchial tree. The main difference lies in the different sources of blood supply, which originate from the pulmonary circulation and the body circulation, respectively. In order to see the origin and location of the masses, more reference can be made to fetal MRI. The prognosis of pulmonary masses is related to their size. Small masses can remain asymptomatic for many years after birth and therefore can be completely removed surgically until after birth with a good prognosis. There are even 15% of fetal CCAM lesions that resolve spontaneously for reasons that are not yet known. In contrast, large masses can be combined with mediastinal displacement and edema in utero, leading to pulmonary dysplasia and heart failure, which can be life-threatening for the fetus if left untreated, and can also lead to mirror image syndrome in the mother with hypertension and edema as the main manifestations. In summary, fetal lung masses should first be clearly diagnosed to determine size and the presence of complications, except for other malformations. For isolated uncomplicated pulmonary masses, we will work together with the pediatric surgery department for a detailed prenatal consultation with the fetal parents to develop a postnatal surgical plan. For fetuses with complications such as edema, we also explain the prognosis and risks clearly to the fetal parents and respect their opinion on the next step of management.