Hydrocele

A hydrocele is a type of swelling in the scrotum that occurs when fluid collects in the thin sheath surrounding a testicle. Hydrocele is common in newborns and usually disappears without treatment by age 1. Older boys and adult men can develop a hydrocele due to inflammation or injury within the scrotum.
A hydrocele usually isn't painful or harmful and might not need any treatment. But if you have scrotal swelling, see your doctor to rule out other causes.
Symptoms
Usually, the only indication of a hydrocele is a painless swelling of one or both testicles.
Adult men with a hydrocele might experience discomfort from the heaviness of a swollen scrotum. Pain generally increases with the size of the inflammation. Sometimes, the swollen area might be smaller in the morning and larger later in the day.