Understanding Scrotal Swelling: Hydroceles & Spermatoceles

What is a Hydrocele?

A hydrocele is a collection of fluid in the thin sheath that surrounds a testicle (the tunica vaginalis). In newborns, they are common and usually disappear on their own. In adult men, they can develop due to an imbalance in the production and absorption of this fluid, or due to inflammation or injury within the scrotum.

The primary symptom is a painless, soft swelling of the scrotum, which might feel like a water-filled balloon. Usually, hydroceles are not dangerous and don't require treatment unless they become very large, causing discomfort or a heavy, dragging sensation.

What is a Spermatocele?

A spermatocele (also known as a spermatic cyst or epididymal cyst) is a painless, fluid-filled sac that forms in the epididymis, the small, coiled tube located on the upper testicle that collects and transports sperm. The fluid within a spermatocele is usually milky and may contain sperm.

Like hydroceles, spermatoceles are typically benign and do not affect fertility. They are often found incidentally during a physical exam and feel like a smooth, firm lump separate from the testicle itself. Treatment is generally not needed unless the spermatocele grows large enough to cause pain or discomfort.

Diagnosis and When to Be Concerned

It is impossible to diagnose the cause of scrotal swelling on your own. A specialist must perform a physical examination. This may involve shining a light through the scrotum (transillumination)—if it's a hydrocele, the light will pass through the fluid. A scrotal ultrasound is often the best way to get a clear image and confirm the diagnosis, differentiating it from other conditions like a varicocele, hernia, or testicular tumor.