Testicular cancer is a disease caused by the uncontrolled growth of abnormal cells in the testicle. This uncontrolled growth causes a lump or tumor.
Cells can break away from the initial tumor to form new growths elsewhere in the body.
Testicular cancer is most common in men under age 35 but can also occur in older men. The actual cause of testicular cancer is unknown. An abnormal growth of cancer cells in the testicle eventually causes the testicle to become enlarged or to develop a lump that can be seen or felt. Men who have or have had an undescended testicle, whether or not it was surgically corrected, have an increased risk of developing testicular cancer. An undescended testicle is a condition in which one or both testicles do not complete the natural passage from inside the abdomen down into the scrotum, which should occur before birth.