RESUMEN
The term cryptorchidism indicates a testis, which has failed to descend to the scrotum and is located at any point along the normal path of descent or at an ectopic site. Hormones play a pivotal role in testicular descent except during the migration to the level of internal inguinal ring. Cryptorchidism is present in about 4.5% of newborns with a higher incidence in preterms. The incidence decreases to 1.2% by the first year. It is classified as palpable and impalpable. The most common site of an ectopic testis is superficial inguinal pouch. Retractile testis is often bilateral and most common in boys between 5 and 6 years of age. Hypospadias and inguinal hernias are the most common associated anomalies seen with undescended testis. A thorough clinical examination helps in arriving at the etiology. A short hCG stimulation test helps to exclude anorchia. Different imaging techniques are of little help in diagnosis and require the help of an experienced radiologist. Laparoscopy has an important role in the diagnosis and management of undescended testis. The common complications include torsion and atrophy of testis. Infertility is seen in about 40% of unilateral and 70% of bilateral cryptorchidism. Undescended testis is 20 to 40 times more likely to undergo malignant transformation than normal testis. Both hCG and GnRH have been used with limited success in these children. All boys with cryptorchidism should be referred to a pediatric surgeon before 2 years of age. These children should be followed up every year after surgery to identify testicular tumors.