There are several causes of varicocele, including congenital factors and secondary causes. Congenital causes are mainly seen in cases of incomplete development of venous valves, while secondary causes may result from prolonged sitting, standing, or intense exercise over time. Some patients develop varicocele due to kidney tumors or blood clots in renal veins, which obstruct the blood flow returning through the spermatic vein. Patients with severe varicocele may experience a sensation of heaviness and pain in the testicles. In treating varicocele, it is also important to understand the reasons behind it. If it is caused by a tumor, active treatment of the tumor is necessary.