Big difference. A hydrocele is fluid around the testicle. Normally, there is some fluid around the testicle to protect it. Excessive fluid is referred to as a hydrocele which can reach the size of a grapefruit. A spermatocele is usually smaller and is along the path of the epidydimis or vas deferens. Occasionally, they can cause pain. Most are asymptomatic and do not require treatment.