Cause
The idiopathic varicocele occurs when the valves within the veins along the spermatic cord do not work properly. This is essentially the same process as varicose veins, which are common in the legs. This results in backflow of blood into the pampiniform plexus and causes increased pressures, ultimately leading to permanent damage to the testicular tissue due to disruption of normal supply of oxygenated blood via the testicular artery.
Varicoceles develop slowly and may not have any symptoms. They are most frequently diagnosed when a patient is 15–30 years of age, and rarely develop after the age of 40. They occur in 15-20% of all males, and it is the main cause of male infertility.
98% of idiopathic varicoceles occur on the left side, apparently because the left testicular vein connects to the renal vein (and does so at a 90-degree angle), while the right testicular vein drains at less than 90-degrees directly into the significantly larger inferior vena cava. Isolated right sided varicoceles are rare.
A secondary varicocele is due to compression of the venous drainage of the testicle. A pelvic or abdominal malignancy is a definite concern when a right-sided varicocele is newly diagnosed in a patient older than 40 years of age. One non-malignant cause of a secondary varicocele is the so-called "Nutcracker syndrome", a condition in which the superior mesenteric artery compresses the left renal vein, causing increased pressures there to be transmitted retrograde into the left pampiniform plexus. The most common cause is renal cell carcinoma (a.k.a. hypernephroma) followed by retroperitoneal fibrosis or adhesions.
Read more about this topic: Varicocele