Spermatocele (/spɜːrˈmætəsiːl/) is a retention cyst of a tubule of the rete testis or the head of the epididymis distended with barely watery fluid that contains spermatozoa. Spermatoceles are the most common cystic condition encountered within the scrotum. They vary in size from several millimeters to many centimeters. Spermatoceles are generally not painful. However, some men may experience discomfort from larger spermatoceles. They are harmless.