Doctors diagnose an epididymal cyst with a physical examination that involves shining a light behind the testicular lump to check to see if the cyst is translucent, explains WebMD. The doctor may recommend an ultrasound to confirm the preliminary diagnosis. Other types of lumps on the testicles include varicoceles and hydroceles, notes Healthline. Lumps may also indicate testicular torsion or cancer.
An epididymal cyst, also called a spermatocele, is a sack of fluid that may contain dead sperm that forms in the epididymis, according to WebMD. This cyst does not affect fertility and may not cause symptoms. If present, symptoms include pain, redness, swelling or pressure at the base of the penis.
Most spermatoceles do not require treatment, but if the cyst restricts blood flow or causes pain, a surgeon may remove the growth, notes WebMD. Sometimes a spermatocele grows large enough to justify surgery, while others may shrink over time. Risks for surgery include regrowth of the cyst or fertility problems caused by damaging the epididymis or the vas deferens, according to Mayo Clinic.
Doctors are unsure why spermatoceles form, although they think that inflammation or trauma to the testicles may increase the chance of developing one, explains Mayo Clinic. There are no known risk factors for spermatoceles except for age; most spermatoceles develop in men between 20 to 50 years of age.