Snapshot A one-year old child is brought to the pediatrician for his 12-month visit. The physician notes that the boy's testicles are inappreciable on exam. The medical record reports that the child's testicles had been examined at two previous visits. The mother is confused and asks if her son will need surgery. Introduction Undescended testicle(s) Most testicles descend by the age of 9 months Once a testicle is found in the scrotum, it is considered "descended" even if on later inspection it is inappreciable Not to be confused with "retractile testicles" that are pulled upward by muscle contraction Epidemiology Most common disorder of sexual differentiation in boys incidence of 3-4% in full term infants more common in preterm infants bilateral in 10% of cases ETIOLOGY Associated with infertility and testicular cancer in adulthood Presentation Symptoms asymptomatic Physical exam no testicle(s) are appreciable in the scrotum the testicle(s) may or may not be found in the abdominal wall above the scrotum Evaluation Diagnosis is based primarily on physical exam Ultrasound may be helpful in identifying undescended testicles in abdominal space Differential Absent testicle(s) Treatment Medical management observation alone indicated until 4 to 6 months at the latest Beta-HCG / testosterone injections indicated after 1yr of age to assist in testicular descension not always successful Surgical intervention orchiopexy indicated in cases where testicle(s) are not descended by 6 months current recommendation is to correct as soon as possible after 4 months of age early removal may prevent infertility and cancer orchiectomy indicated in cases when testicle is found in the abdominal space later in life Complications Decreased fertility and in some cases infertility Malignancy 4 to 10-fold increased risk of developing cancer in both testicles, if even one is undescended peak age of malignancy is 15-45 years seminoma is most common malignancy orchiopexy does not decrease risk of cancer improves prognosis by earlier detection Torsion Hernias Prognosis Very good to excellent in most cases Most descend spontaneously by 1 year of age