The pathogenesis of congenital laryngeal cyst is not clear. The causes include the abnormal development of the gill fissure, the dysplasia of the larynx, the obstruction of the laryngeal air bag and the mucous duct, and the theory of the ectopic thyroid. Histologically, most congenital laryngeal cysts are confined to respiratory epithelium, while others include stratified squamous epithelium, columnar epithelium, cuboidal epithelium and some mixed epithelium. In more than half of the cases, diffuse or aggregated lymphatic tissue can be observed. At present, congenital laryngeal cysts are divided into two things types: type I, cyst confined to the laryngeal cavity (Fig. 18.1), type II, cyst extending to the larynx. The latter can be further divided into type IIa derived from embryos and type IIb derived from inner and mesoderm [1].