Pectus excavatum can be divided into two categories: The first type is simple pectus excavatum, and the second type is pectus excavatum combined with other diseases. Simple pectus excavatum is a condition in itself and can exist independently, meaning that children with pectus excavatum may not have other pre-existing diseases. Of course, there is also pectus excavatum combined with other diseases, the most common of which are connective tissue disorders, where the incidence of pectus excavatum is significantly higher among patients. This suggests that pectus excavatum may be closely related to the genes that promote or inhibit cartilage development. Additionally, pectus excavatum may also be related to diseases in patients with congenital diaphragmatic hernia. Some cases of congenital Marfan syndrome may also be related, as well as some children who might have airway stenosis or congenital diseases of the lungs and bronchi. These types of congenital diseases may also be accompanied by pectus excavatum. In summary, whether it is simple pectus excavatum or that combined with other diseases, it can itself form a pathological condition and may also be accompanied by other congenital diseases, leading to secondary pathological changes.