The scrotum (the sac that surrounds and protects the testes) may swell on one or both sides. Swelling can be small and detectable only by carefully feeling the scrotum, or it may be very large and easily visible. Some disorders that cause swelling of the scrotum are painful (see Scrotal Pain).
Painless swelling of the scrotum can be caused by generally harmless conditions or can be a sign of cancer. There are several causes.
The most common causes are
A hydrocele is a disorder in which fluid collects between layers of tissue that surround the testis. Hydrocele and inguinal hernia are the most common causes among boys. Up to 20% of men have a varicocele, which can cause infertility.
Less common causes include
Cancer of a testis is the most concerning cause of painless scrotal swelling. Most often swelling does not turn out to be cancer. But cancer of a testis is the most common solid cancer in men younger than 40 years and it also can occur in younger and older men, so any testicular swelling or lump should be checked by a doctor.
The following information can help men know how quickly to see a doctor and what to expect during the evaluation.
Men who have a balloon-like swelling that extends from the abdomen into the scrotum and cannot be pushed back could have an inguinal hernia that has become trapped (incarcerated). They should see a doctor right away. If a painless swelling suddenly becomes painful, men should also see a doctor right away because the cause may be an inguinal hernia that has become trapped and the blood supply shut off (strangulated hernia). Other men should see a doctor when an office appointment is available. A delay of a week or so is not harmful.
Doctors first ask questions about the man's symptoms and then do a physical examination. What they find during the history and physical examination often suggests a cause of the swelling and the tests that may need to be done (see Table: Some Causes and Features of Scrotal Swelling).
Doctors ask how long the swelling has been present and whether there is any change in the swelling when the man stands up or lies down or when abdominal pressure increases (such as with coughing or straining to lift something). Doctors also ask about the man's medical history because disorders in other parts of the body (for example, edema related to heart failure or liver failure) may contribute to scrotal swelling.
The physical examination is done with the man standing and lying down. The doctor carefully feels the testis, epididymis, and spermatic cord to detect the exact location of the swelling or lump, and whether the swelling is tender. Sometimes the doctor shines a bright light behind the scrotum to see if light passes through (transillumination). Light can often pass through a collection of fluid (such as a hydrocele) but not through a solid lump (such as a cancer).
Some Causes and Features of Scrotal Swelling
Sometimes the doctor can determine the cause of the swelling based on the symptoms and the results of the physical examination. If the symptoms and physical examination do not reveal the cause, testing is usually needed. Often the first test is ultrasonography. Ultrasonography is done when
Depending on the results of ultrasonography, further testing may be done for cancer of a testis. Testing for testicular cancer includes blood tests and sometimes computed tomography (CT) of the abdomen, pelvis, and chest.