An epididymal cyst, often called a spermatocele, is a common, benign, fluid-filled sac located within the scrotum. These cysts are not cancerous and do not increase the risk of developing testicular cancer. They are prevalent, with estimates suggesting up to 30% of men may have a small, unnoticed spermatocele. Although the discovery of a scrotal lump often causes anxiety, this type of cyst is usually harmless and does not require intervention.
Defining the Condition and Location
An epididymal cyst forms on the epididymis, a long, tightly coiled tube situated along the back and top surface of each testicle. This structure stores and transports sperm from the testicle to the vas deferens. The cyst itself is a smooth, well-defined, fluid-filled mass that grows out of the epididymis.
The terms “epididymal cyst” and “spermatocele” are often used interchangeably. Technically, a spermatocele specifically contains fluid that includes dead or living sperm cells, while an epididymal cyst contains clear or milky fluid. Both masses are considered extratesticular, meaning they are separate from the testicle, and typically arise from the head of the epididymis.
Causes and Risk Factors
The precise cause for the formation of an epididymal cyst is often unknown, meaning the condition is considered idiopathic. The most accepted theory suggests a blockage or dilation in one of the small ducts of the epididymis that transport sperm. This obstruction causes fluid and materials to back up, leading to the formation of the sac.
This blockage may result from prior trauma or injury to the scrotum, which causes scarring in the epididymal tubes. Inflammation or infection of the epididymis (epididymitis) is another potential factor contributing to duct obstruction. Although cysts can occur at any age, they are most frequently seen in middle-aged men, making increasing age a primary risk factor.
Clinical Presentation and Diagnosis
Most epididymal cysts are small and asymptomatic, discovered incidentally during a self-examination or routine physical exam. When symptoms occur, they usually involve a feeling of fullness or heaviness in the scrotum. Patients may notice a soft, distinct lump that feels separate from the testicle, often located at the top or behind it.
A medical professional conducts a physical examination to feel the lump and determine if it is separate from the testicle, which helps differentiate it from a testicular mass. Transillumination may be performed, where a light is shone through the scrotum; if the mass is fluid-filled, the light will pass through it. For a definitive diagnosis, a scrotal ultrasound is typically ordered. This non-invasive imaging test confirms the cystic nature of the mass and provides a clear image of the underlying testicle.
Treatment Options and Monitoring
The management strategy for most epididymal cysts is conservative, centered on observation, often called watchful waiting. Because these cysts are benign and usually asymptomatic, no treatment is necessary in the majority of cases. Regular self-examinations and follow-up appointments are advised to monitor the cyst for any changes in size or symptoms.
Intervention is reserved for cysts that cause persistent pain, significant discomfort, or interfere with daily activities. Needle aspiration, where the fluid is drained, is an option, but it is rarely recommended as a long-term solution due to high rates of fluid reaccumulation. The definitive treatment is surgical excision, known as a spermatocelectomy, which removes the cyst entirely through a small incision in the scrotum. This outpatient procedure carries a small risk of recurrence or damage to the epididymis, which is a consideration for men concerned about fertility.