Men should regularly perform testicular self-exams to look for lumps, the majority of which are not cancerous and likely to be caused by fluid collecting, an infection, or swelling of skin or veins. For example, a “cyst” is a fluid-filled sac that feels like a small, hard lump but is usually harmless. A “varicocele” is a lumpy area caused by swollen veins in the testicles, and a “hydrocele” is a painless collection of fluid around the testicle that occurs after an infection or injury to the area. However, “testicular torsion” is a serious medical problem that causes severe pain and requires immediate medical attention. It occurs when the cord connected to the testicles twists and cuts off the blood supply.
P.S. A hard lump or swelling that forms on the front or side of the testicle is often the first sign of testicular cancer. Although the entire testicle may feel firmer than usual, most tumors do not cause any pain.