A lump on a testicle is an abnormal swelling or mass found within the scrotum. While the immediate fear often points toward malignancy, the reality is that the majority of testicular lumps are caused by benign conditions, such as fluid collections, infections, or structural issues. It is impossible to determine the cause without professional medical evaluation, and any new lump or change must be assessed by a healthcare provider without delay. Understanding the various causes can help manage anxiety, but it should not replace a doctor’s diagnosis.
Lumps Caused by Fluid Collection
One common source of scrotal swelling is the accumulation of fluid, which typically results in a smooth, painless lump. A hydrocele occurs when fluid collects in the thin sheath that surrounds the testicle, called the tunica vaginalis. This causes the testicle to feel enlarged and is often described as a fluid-filled balloon that obscures the ability to feel the underlying testicle. Hydroceles can develop due to injury, inflammation, or an imbalance in fluid production and absorption.
A spermatocele, also known as an epididymal cyst, is another common benign lump. This cyst develops in the epididymis, the coiled tube located on the back of the testicle. Spermatoceles are filled with a milky or clear fluid that may contain sperm, and they typically feel like a smooth, distinct lump positioned above or behind the testicle itself. Both hydroceles and spermatoceles are often diagnosed using a process called transillumination, where a light shone through the scrotum will illuminate the fluid-filled mass.
Lumps Caused by Inflammation or Infection
Inflammatory conditions often cause a painful lump accompanied by symptoms. Epididymitis is the inflammation of the epididymis, which creates a swollen, tender mass usually located at the back of the testicle. This condition is frequently caused by a bacterial infection, often from a sexually transmitted infection (STI) in younger men or a urinary tract infection (UTI) in older men.
The inflammation can cause the entire scrotum to become red, warm, and swollen, sometimes leading to a reactive hydrocele. Orchitis refers to the inflammation of the testicle itself, which is less common and often caused by a viral infection, such as the mumps virus. When both the testicle and epididymis are involved, the condition is called epididymo-orchitis, presenting as a painful, hardened mass accompanied by symptoms like fever, painful urination, or discharge.
Lumps Caused by Vein Enlargement and Structural Issues
A varicocele is an enlargement of the veins within the spermatic cord. This condition is similar to a varicose vein in the leg and results from faulty valves that cause blood to pool. Varicoceles are often described as feeling like a “bag of worms” above the testicle and are most common on the left side due to anatomical differences. The lump may become more prominent when standing and can sometimes cause a dull ache, particularly with physical activity.
Another structural cause is an inguinal hernia, where a portion of the intestine or abdominal tissue protrudes through a weak spot in the abdominal wall and descends into the scrotum. This typically presents as a bulge that increases in size when coughing, straining, or standing, and it may be accompanied by a heavy or dragging sensation in the groin.
Identifying Testicular Cancer
While the majority of lumps are benign, the most serious cause is cancer, which is the most common cancer in men aged 15 to 35. A cancerous lump typically presents as a painless, firm mass or hardness within the testicle itself, not separate from it like an epididymal cyst. The mass can be much larger, and it usually involves the front or side of the testicle. Other characteristic symptoms include a feeling of heaviness in the scrotum, a dull ache in the lower abdomen or groin, or a sudden collection of fluid around the testicle.
Any change in the size or feel of a testicle should be investigated, even if it is not painful. Regular self-examinations are recommended to become familiar with the normal texture and size of the testicles, which can help detect subtle changes early. Early diagnosis of testicular cancer leads to an excellent prognosis, making prompt medical attention crucial.
Immediate Medical Attention and Diagnosis
The most urgent scenario is testicular torsion, which occurs when the testicle twists on the spermatic cord, cutting off its blood supply. This presents as a sudden, severe, and rapidly worsening pain in the testicle, often accompanied by nausea and vomiting. Testicular torsion is a time-sensitive emergency, as the testicle can be permanently damaged if blood flow is not restored within about six hours.
A doctor will begin the diagnostic process with a thorough physical examination, feeling the location, size, and texture of the lump and checking for associated symptoms. Imaging with a scrotal ultrasound is the primary tool used to differentiate causes, as it visualizes whether the lump is a solid mass, a fluid collection, or enlarged veins. Blood tests may also be utilized to check for signs of infection or, in the case of a solid mass, to measure tumor markers that can indicate the presence of cancer.