Varicocele - Mayo Clinic. Sometimes a vein over your testicle can swell. Varicoceles are common and usually form during puberty, though they can also be found in adult males. It occurs in about one in six males, but unlike varicose veins in the legs, it is more common in younger males, ages 15- 25. Varicose syphoma. A varicocele is an enlargement of the veins within the scrotum. You may also have pain, swelling, heaviness, and achiness over or around the enlarged veins. What is a Varicocele? Varicocele, an enlargement of the veins within the scrotum, is not unlike the varicose veins that appear in the legs. Though it' s harmless, this condition - - called varicocele - - can be painful. The primary symptoms of varicose veins are highly visible, misshapen veins, usually on your legs.