Cryptorchidism refers to the failure of the testes to descend from the lumbar retroperitoneum to the scrotum in accordance with normal developmental procedures. The incidence of cryptorchidism decreases gradually during growth and development, and is about 30% in preterm infants, 4% in newborns, 0.66% at 1 year of age, and 0.3% in adults, indicating that the descent of the testis is a gradual process and that the testis can continue to descend after birth. However, after 6 months of age, the chance of continued descent decreases significantly. Symptoms: The main manifestation is flattening of the scrotum on the affected side, asymmetry of the left and right scrotum in unilateral cases, and empty and deflated scrotum in bilateral cryptorchidism. If the cryptorchid is twisted, if the cryptorchid is located at the inguinal canal or the external ring, the main manifestation is a local painful mass, no normal testicle in the scrotum of the affected side, and mild gastrointestinal symptoms. If the cryptorchid is located in the abdomen, the painful site after torsion is in the lower abdomen near the inner ring. The symptoms and signs of right intra-abdominal type cryptorchid torsion are quite similar to those of acute appendicitis, and the main difference is that the pressure point of intra-abdominal cryptorchid torsion is low and near the inner ring. Classification: ① intra-abdominal testis, the testis is located above the inner ring; ② intra-inguinal canal testis, the testis is located between the inner and outer rings; ③ ectopic testis, the testis deviates from the normal descending path from the abdominal cavity to the scrotum; ④ retracted testis, the testis can be pushed or pulled into the scrotum and then retracted up to the groin after being released. The testicles of cryptorchidism are generally small in size, soft in texture and poor in elasticity, and sometimes the testicles and epididymis are separated or there is no epididymis. If the testes are left in the abdominal cavity and inguinal canal for a long time, the “high temperature” in the body can cause degenerative changes or even fibrosis in the varicocele of the testes, which is the spermatogenic base, and the spermatogenic cells cannot be produced, and the endocrine function is also abnormal. The endocrine function is also abnormal, so it is impossible to have children normally. Therefore, cryptorchidism should be treated in time. Treatment Cryptorchidism is usually treated by two methods: endocrine treatment and surgical treatment. Endocrine therapy is mainly used in China to promote the secretion of androgen testosterone to make the testes fall on their own. Surgical treatment The aim of surgical treatment is to restore the normal physiological environment of the testes and to keep them at a normal temperature in the scrotum in order to maintain the patient’s fertility and to minimize complications such as malignant changes. Currently, surgery is advocated to be performed around the age of 1 year. Since the risk of malignant change in ventral cryptorchidism is several times higher than that of normal testis, ventral cryptorchidism should be treated surgically as early as possible.