The epididymis is actually a six meter long thin tube that is rolled into a ball and attached to the testicle, and the continuation of the epididymis is the vas deferens. The lumen of the duct is very thin, but the wall of the duct has very thick muscles. It is responsible for transporting the sperm from the testes to the urethra. Why it is so long, no one knows, but I guess it is so that the fastest sperm will win. The epididymis is derived from the mesonephros (middle kidney) during embryonic development. Most of the mesonephros disappear of their own accord, but some of the tubes that do not disappear can become epididymal cysts. If this cyst contains spermatozoa at puberty, it is called a seminal cyst. The diagnosis can be confirmed by ultrasound. Some cysts are single, and some are multicystic. In the latter case, they feel like a bunch of grapes. If there are no symptoms, it can be observed. If there are symptoms, pain and enlargement, then removal should be considered. The surgery is performed on the same day, and some patients may experience temporary edema after surgery. Damage to the vas deferens or the epididymis itself should be avoided as much as possible.