There can sometimes formed fluid-filled blisters, cysts, in the channels connecting the testicles and bitestiklen and sperm passesthrough. Cysts can be quite large, because their liquid contents gradually increased. But despite this condition is harmless. Cysts in bitestiklerne is quite common. A single or a few cysts occur in many women after 40 years of age. The cysts often manifests itself as a swelling in the rear, the upper part of one or both testicles. There is no pain.