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Scrotal Swelling

by Anuja P. Shah, MD

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).

Causes

Painless swelling of the scrotum can be caused by generally harmless conditions or can be a sign of cancer. There are several causes.

Common causes

The most common causes are

  • A collection of fluid in the scrotum (hydrocele)

  • A hernia in the groin (inguinal hernia)

  • Widening of the veins that carry blood from a testis (varicocele)

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

Less common causes include

  • A cyst in the epididymis (spermatocele)

  • A collection of blood in the scrotum (hematocele)

  • Accumulation of excess fluid in the body (edema)

  • Cancer of a testis

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.

Evaluation

The following information can help men know how quickly to see a doctor and what to expect during the evaluation.

Warning signs

In men with a lump in the scrotum, the most concerning signs are

  • A solid lump that is attached to or part of the testis

  • A balloon-like bulge that extends from the abdomen into the scrotum and cannot be pushed back


When to see a doctor

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.


What the doctor does

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

Cause

Common Features*

Tests

Edema (accumulation of excess fluid in the body)

Swelling that

  • Feels spongy

  • Occurs on both sides throughout the scrotum

  • Remains indented after pressure is applied and removed (called pitting edema)

Often in men with swelling in the legs and sometimes abdomen

In men with disorders that can cause swelling such as heart failure or a severe liver or kidney disorder

A doctor's examination

Sometimes ultrasonography

Hematocele (a collection of blood in the scrotum)

Swelling that

  • Is painful and tender

  • Develops after an injury

A doctor's examination

Sometimes ultrasonography

Hydrocele (a collection of fluid in the scrotum)

Swelling that

  • Feels soft

  • Does not disappear when lying down

  • Cannot be pushed back into the abdomen

A doctor's examination

Sometimes ultrasonography

Inguinal hernia (a hernia in the groin)

Typically in men who have had a painless bulge in the groin for a long time, often in those already known to have a hernia

A bulge that

  • Feels soft and balloon-like

  • Often can also be felt above the scrotum

  • Typically enlarges when men are in an upright position or when pressure within the abdomen increases (for example, when bearing down as if having a bowel movement or when doing heavy lifting)

  • Sometimes disappears when lying down

  • Can sometimes be pushed back into the abdomen

Sometimes pain that begins gradually or suddenly, typically when the bulge cannot be pushed back into the abdomen

Only a doctor's examination

Lymphedema (accumulation of lymph fluid)—for example, due to a tropical worm infection called filariasis or present from birth

Rubbery swelling throughout the scrotum

No indentations when the area is pressed

A doctor's examination

Sometimes ultrasonography

Spermatocele (a cyst in the epididymis)

A lump near the top of the testis

A doctor's examination

Sometimes ultrasonography

Testicular cancer

A hard lump attached to or in the testis

Possibly dull, aching pain or, if the cancer bleeds, sudden sharp pain

Ultrasonography

Blood tests

Sometimes CT of the abdomen, pelvis, and chest

Varicocele (widening of the veins that carry blood from a testis)

Swelling that

  • Feels like a bag of worms

  • Usually occurs on the left side

Possibly pain and a feeling of fullness when standing

Possibly a shrunken testis (testicular atrophy)

Only a doctor's examination

*Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present.

CT = computed tomography.


Testing

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

  • Doctors are unsure of the diagnosis

  • Doctors detect a hydrocele during the examination (ultrasonography may show the source of the fluid)

  • Transillumination does not show fluid in the area of swelling

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.


Treatment

The best way to treat scrotal swelling is to treat the cause of the swelling. Treatment is not always needed. Sometimes doctors try to reduce an inguinal hernia by pushing gently against the protruding intestine and forcing it back into place.

Key Points

  • Men and boys with scrotal swelling, even if it does not cause pain, should see a doctor.

  • Cancer of a testis is a concern in all boys and men, especially those who are younger than 40.

  • The diagnosis is usually evident from the symptoms, physical examination findings, and ultrasonography.

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