A scrotal mass is an abnormal bulge or lump inside your scrotum. The scrotum is a sac of skin that contains your testicles.

A scrotal mass can be a swollen testicle or it can contain fluid or other tissue. It’s possible that your mass could be cancerous, but there are also a number of causes for a noncancerous mass in your scrotum.

The symptoms you experience as a result of your scrotal mass will vary depending on their cause. In some cases, there aren’t any symptoms other than a mass that you can feel with your fingers.

Other symptoms you might experience include:

  • sudden pain or dull ache in your scrotum
  • pain that spreads to your groin, abdomen, or back
  • hard or swollen testicles
  • feeling of heaviness in your scrotum
  • a swollen, tender epididymis, which is the tube located behind your testicles that stores and transports sperm
  • a swollen scrotum
  • redness of the scrotum

If the cause of your scrotal mass is an infection, you might have a fever and feel you need to urinate more often. There might also be blood or pus in your urine.

Many conditions can cause scrotal masses.

Epididymitis

Epididymitis is inflammation of the epididymis. Epididymitis is most often caused by a sexually transmitted infection (STI), such as chlamydia.

Hydrocele

A hydrocele occurs when one of the naturally occurring sacs that surround each testicle fills with fluid. These sacs normally contain a small amount of fluid. If the fluid collects, swelling can occur.

Cancer

Testicular cancer starts out as abnormal cells in the testicles and can be a potential cause of scrotal masses.

Other potential causes of a scrotal mass include:

  • twisting of the nerves that connect your penis to your testicles
  • hernia
  • enlarged veins in your scrotum
  • inflammation of your testicle caused by a virus such as the mumps

Some causes of scrotal masses don’t require immediate attention. However, it’s generally a good idea to talk with your doctor about any masses in your scrotum. Some causes of scrotal masses can cause permanent damage to your testicles. Your doctor can help properly diagnose and treat any masses you find.

If your scrotal mass is the result of a bacterial infection, antibiotics will be a part of your treatment. If you have a viral infection, the best course of treatment is rest and pain medication.

Depending on the size, your doctor may simply leave the mass alone. If the mass is noncancerous and doesn’t cause you severe pain or discomfort, you may not need treatment. If your mass causes you discomfort, it might be removed. This can be done surgically or your mass might be drained of fluid as is done for a hydrocele.

If the masses in your scrotum are caused by cancer, you should see a cancer treatment specialist to evaluate whether or not you’re a good candidate for treatment. Important factors in determining if cancer treatment is right for you are your age, your overall health, and whether the cancer has spread outside of your testicles.

Treatments for cancer include:

  • radical inguinal orchiectomy, which involves the surgical removal of your affected testicle and the tube that connects it to your body
  • radiation therapy using beams of X-rays to destroy cancer cells that can be left behind after surgery
  • chemotherapy using powerful drugs to kill cancer cells

You can help prevent scrotal masses caused by STIs by practicing safe sex. While using protection isn’t 100 percent effective against all STIs, it can reduce your risk.

Wear a cup while playing sports to protect your testicles from injury. Checking your scrotum and testicles for lumps each month can help you and your doctor detect any problems as early as possible.