An epididymal cyst is a common, fluid-filled sac that develops in the epididymis, the coiled tube located behind the testicle. This condition is almost always benign, meaning it is non-cancerous and does not pose a serious health risk. The lump is generally felt as a separate, soft mass near the testicle, but typically remains small and does not require treatment.
Anatomy and Formation of Epididymal Cysts
The epididymis is a coiled tube resting along the back and top of the testicle that stores and transports sperm. An epididymal cyst forms when a blockage or dilation occurs in one of the small ducts within the epididymis. This obstruction leads to the accumulation of fluid, resulting in the formation of a cyst.
The fluid within a simple epididymal cyst is typically clear, but if it contains sperm cells, the mass is technically classified as a spermatocele. Clinically, the terms epididymal cyst and spermatocele are often used interchangeably because they are both benign, fluid-filled masses arising from the epididymis. Spermatoceles usually arise from the head of the epididymis, while simple cysts may occur anywhere along the structure.
The precise cause of these blockages is often unknown, leading them to be classified as idiopathic. However, cysts may form due to trauma, inflammation, or scarring that obstructs the epididymal tubules. These cysts generally do not interfere with sexual function or fertility.
Symptoms and Clinical Presentation
Most epididymal cysts are asymptomatic, meaning they cause no noticeable symptoms. They are frequently discovered as a painless, soft, movable lump during a self-examination or routine physical exam. The mass is distinct and separate from the testicle, which helps differentiate it from more serious conditions.
Symptoms may appear if the cyst grows large enough to exert pressure on surrounding structures. Patients might experience a feeling of heaviness or a dull ache in the scrotum. A large cyst can also cause discomfort or noticeable swelling.
Any new lump or swelling in the scrotum should prompt a visit to a healthcare provider for a professional evaluation. While epididymal cysts are overwhelmingly benign, a medical examination is necessary to rule out other, more serious causes of a scrotal mass, such as testicular cancer. In rare cases, if a cyst twists (torsion), it can cause sudden, severe scrotal pain that requires immediate medical attention.
Diagnosis and Treatment Options
Diagnosis begins with a physical examination, where the provider assesses the location, size, and texture of the scrotal mass. The provider often uses transillumination, shining a light through the scrotum, to confirm the fluid-filled nature of the lump. This technique helps distinguish the cyst from a solid tumor.
The definitive diagnostic tool is a scrotal ultrasound, which provides a detailed image of the cyst’s size, location, and composition. Ultrasound confirms it as a fluid-filled lesion and is performed to thoroughly examine the testicle. This imaging is the most reliable way to exclude testicular cancer or other conditions like a hydrocele.
Treatment is generally reserved for cysts that are large, symptomatic, or causing significant discomfort. For small, asymptomatic cysts, the strategy is watchful waiting, involving periodic monitoring. Over-the-counter pain relievers can manage any mild discomfort associated with the cyst.
Surgical excision, known as spermatocelectomy or epididymectomy, is the most common definitive treatment for large or painful cysts. This outpatient procedure involves making a small incision in the scrotum to carefully remove the cyst while preserving the surrounding epididymis and testicle. A less common technique, aspiration, involves draining the fluid with a needle, but this method is associated with a high rate of recurrence as the fluid often reaccumulates.