What is a spermatocele?

A spermatocele is a non-cancerous fluid-filled space that develops in a part of the testicle called the epididymis. Some spermatoceles develop as a result of a blockage in one of the tubes that carry sperm out of the testicle. While most small spermatoceles will resolve on their own over time, large spermatoceles can cause pain and may need to be surgically removed.


This article will help you read and understand your pathology report for spermatocele.

The male reproductive tract

Testicles and scrotum

The testicles, or testes, are part of the male reproductive system. A man has two testicles, which are egg-shaped organs that when fully matured measure approximately 5 cm in the greatest dimension. The testicles are each suspended by a structure called the spermatic cord, which is composed of connective tissue and muscle. The testicles are covered in a fleshy sac of skin called the scrotum. The scrotum hangs between the legs and beneath the penis. After puberty, the testicles are responsible for making sperm. The testicles also produce testosterone, which is a male sex hormone.

Seminiferous tubules

The tissue within the testicles is made up of hundreds of tiny tubes called seminiferous tubules. The seminiferous tubules are lined by millions of specialized cells called germ cells. Germ cells are responsible for the production of sperm (spermatozoa), which occurs through a process called spermatogenesis. The sperm produced within the seminiferous tubules travels through a series of ducts to eventually reach a coiled structure called the epididymis.


An epididymis sits on top of each testicle. Immature sperm are stored and mature within the epididymis. During ejaculation, sperm is pushed from the epididymis and into the vas deferens which is a tubular structure residing within the spermatic cord. The vas deferens eventually joins with the seminal vesicle of the prostate to form the ejaculatory duct. The sperm then passes through ducts within the prostate to empty into the urethra and exit out the tip of the penis.

male genital tract

How is the diagnosis of spermatocele made?

Your doctor may suspect that you have a spermatocele after performing a physical examination. During this examination, your doctor may shine a light on your scrotum. Because a spermatocele is filled with fluid, light can pass through it. Doctors describe this as ‘transillumination’. In contrast, a solid growth (such as a tumour) would not allow light through. Your doctor may also perform a test called an ultrasound. This test allows your doctor to see inside the scrotum. When examined by ultrasound, a spermatocele will appear as an open fluid-filled space called a cyst.

The diagnosis can also be made after the spermatocele is surgically removed and the tissue is sent to a pathologist for examination under the microscope. When examined under the microscope, the spermatocele appears as an open space surrounded by a thin wall. The cells lining the wall are similar to those normally found in the epididymis. For example, cells with small finger-like projections called cilia are found in the normal epididymis and are commonly seen in a spermatocele. Sperm and fluid may be seen within the space in the center of the spermatocele.

by Jason Wasserman MD PhD FRCPC (updated November 19, 2021)
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