Each scrotal condition has its own underlying cause. Varicoceles develop when the one-way valves inside the spermatic veins fail, allowing blood to pool and the veins to dilate. They occur much more often on the left side because of the way the left testicular vein connects to the left renal vein at a sharper angle, increasing back pressure. Most varicoceles arise during puberty and gradually become more noticeable in adulthood.
Hydroceles in adult men typically form when fluid accumulates faster than the body can reabsorb it, often following inflammation, infection (such as epididymitis), trauma, or as a complication of a hernia repair, vasectomy, or other scrotal surgery. In newborns, congenital hydroceles result from incomplete closure of the processus vaginalis during fetal development.
Spermatoceles arise from blockage or dilation of the small tubules of the epididymis where sperm mature and are stored. Aging is the strongest risk factor, and most spermatoceles are discovered incidentally during a physical exam or scrotal ultrasound performed for another reason. According to the American Urological Association, the vast majority of spermatoceles do not affect fertility or testicular function.
