A mass in the scrotum. If a varicocele is large more than enough, a mass like a "bag of worms" may very well be obvious over the testicle. A smaller sized varicocele might be much too little to view but apparent by touch. So in numerous ways, it's a cycle. https://www.sgvascularctr.com/what-are-veins-and-why-should-i-know-about-them/