Hydrocoele is a collection of fluid around the testicle. This is not a cancerous condition. The fluid is secreted by the sac surrounding the testicle, called the tunica vaginalis. For reasons not fully understood, sometimes there is an imbalance between production and reabsorption of this fluid, resulting in gradual accumulation of fluid around the testicle and an enlarging swelling of the scrotum on that side. This can occur slowly over many years, but eventually leads to pain and discomfort with daily activities.
Some doctors try treating the condition by sucking the fluid out with a needle and syringe, and while this may provide temporary relief, it can cause infection and inevitably the fluid returns. Definitive treatment involves an operation to open up the sac containing the testicle and remove the fluid, and then removing most of this sac so that the fluid cannot be produced in future. This generally works well with a high long-term success rate. The operation is performed though the scrotum and can be done as a day surgery procedure.