A scrotal mass can cause concern, especially when a man is actively trying to conceive. Epididymal cysts, often called spermatoceles, are common and frequently discovered incidentally during routine exams or imaging. These benign growths raise questions about their potential to interfere with reproduction. However, most medical evidence suggests these cysts are not a significant cause of low sperm count.
Understanding Epididymal Cysts
An epididymal cyst is a fluid-filled sac that forms within the epididymis, the coiled tube situated behind the testicle. While “spermatocele” is often used synonymously, a spermatocele specifically contains sperm cells, distinguishing it from a simple cyst containing only clear fluid. These structures are non-cancerous and benign, posing no threat to general health or sexual function.
The epididymis is a single, winding duct next to the testis, measuring several meters in length if uncoiled. This organ is responsible for the storage, maturation, and transport of sperm to the vas deferens. Cyst formation occurs when a small tubule connecting the testicle to the epididymis becomes obstructed, causing fluid to accumulate. Epididymal cysts are common, found in over 70% of men undergoing fertility evaluation.
The Mechanism of Sperm Production and Transport
Sperm production begins in the testes through a complex biological process known as spermatogenesis. Immature sperm travel into the epididymis, spending several days to two weeks undergoing maturation. During this transit, the sperm acquire motility and gain the capacity to fertilize an egg.
The epididymis has three regions—the head, body, and tail—each playing a role in sperm development and storage. Mature sperm are stored in the tail before being propelled into the vas deferens, which carries them toward the seminal vesicles and prostate gland. This journey is a coordinated transport system necessary for healthy ejaculation.
Low sperm count, medically termed oligospermia, occurs when sperm concentration in the ejaculate falls below a threshold. This reduction results from two primary issues: a problem with sperm production in the testes, or a physical blockage along the transport pathway. Understanding this two-part mechanism—production and transport—is fundamental to assessing how a physical mass might interfere with fertility.
Direct Impact on Sperm Count and Fertility
Despite their anatomical proximity, epididymal cysts rarely cause a clinically significant drop in sperm count or overall fertility. Clinical research has found no statistically significant association between these cysts and impaired semen parameters, such as sperm concentration, motility, or morphology. The vast majority of cysts are small, do not obstruct the epididymal duct, and therefore do not interfere with sperm passage into the vas deferens.
A theoretical risk for low sperm count exists, but it is reserved for rare instances involving a very large cyst. A cyst of substantial size may exert pressure to obstruct or compress the epididymal tube, potentially leading to obstructive azoospermia (no sperm in the ejaculate) or severe oligospermia. In these rare cases, the cyst physically blocks the outflow of sperm that are otherwise being produced normally in the testis.
The presence of an epididymal cyst does not typically affect sperm production within the testis itself. The cyst is a downstream issue of the transport system. Therefore, most cysts do not require intervention unless they cause discomfort or are confirmed to be the single cause of an obstructive fertility problem.
Treatment Options When Fertility is Compromised
When a man with an epididymal cyst has difficulty conceiving, a thorough fertility evaluation is necessary to confirm the cyst is the cause, rather than other factors like varicoceles or hormonal imbalances. Evaluation begins with a semen analysis to determine if low sperm count or azoospermia is present. If an obstruction is suspected, further testing locates the precise point of blockage.
For the rare case where a cyst is definitively implicated in obstructing sperm flow and fertility is desired, the primary intervention is surgical excision, known as a spermatocelectomy. This procedure involves carefully removing the cyst while preserving the epididymis and surrounding structures to maintain the sperm transport pathway. While effective, the surgery carries a small risk of scarring or damaging the epididymis, which could create a new blockage and worsen the fertility outcome.
Alternative procedures like needle aspiration (draining the fluid) or sclerotherapy (injecting a solution to prevent refilling) are generally not recommended when fertility is a concern. These methods carry a higher risk of damaging the epididymal tubules, potentially causing inflammation or scarring that could permanently obstruct sperm passage. Therefore, conservative management through observation is the standard approach for asymptomatic cysts, even during fertility assessments.