Solitary Liver Lesions Found on Imaging

During an ultrasound, a computed tomography (CT) or a magnetic resonance (MR) scan, a single lesion, nodule or mass may sometimes be found in the liver. This is called a “solitary liver lesion”, or more generally a “focal liver lesion”.

Seeing a lesion in the liver does not mean that the person has cancer.

A substantial proportion of liver lesions found by chance on an ultrasound or a CT done for another reason are benign. But what the lesion is has to be established properly.

Why might a single lesion form in the liver?

A single lesion seen in the liver can have many causes.

The benign lesions met with often include:

• A simple liver cyst,
• A haemangioma,
• Focal nodular hyperplasia (FNH),
• A hepatocellular adenoma.

Less often, the lesion imaged may be due to causes such as:

• Hepatocellular carcinoma (HCC),
• Cholangiocarcinoma,
• The spread of a cancer from another organ to the liver (metastasis),
• Infection or an abscess.

For this reason it is not enough to say only “there is a lesion”; the characteristics of the lesion have to be established.

The first question in assessment: is the liver healthy?

One of the most important points in assessing a liver lesion is the general state of the patient’s liver.

For instance:

• a small lesion found by chance in a healthy person without cirrhosis, without a history of hepatitis B or C, and with no known cancer, and
• a new lesion appearing in a person with cirrhosis or chronic hepatitis B

are not assessed in the same way.

In the second case, more careful investigation is needed for liver cancer.

Why does the patient’s history matter?

The doctor may ask in particular about:

• Whether there has been a previous diagnosis of cancer,
• Hepatitis B or hepatitis C,
• Cirrhosis or chronic liver disease,
• Alcohol,
• Fatty liver and metabolic disease,
• The medicines taken,
• Contraceptive pills or hormone treatments,
• Use of anabolic steroids,
• Symptoms such as weight loss, fever or night sweats,
• Family history.

Certain hormones and anabolic steroids, for instance, can be associated with the development of a hepatocellular adenoma.

What is a haemangioma?

A liver haemangioma is one of the commonest benign tumours of the liver.

It is made of blood vessels and is mostly found by chance during an ultrasound done for another reason. Most are small and cause no symptoms at all.

Where the imaging features are typical, the diagnosis can generally be made by imaging alone.

Does a haemangioma turn into cancer?

A typical haemangioma is not a cancer and is not generally expected to turn into one.

Treatment is not needed in the great majority of haemangiomas whose diagnosis is established and which cause no symptoms.

Where the imaging findings suggest a typical haemangioma, an unnecessary biopsy is avoided.

What is focal nodular hyperplasia (FNH)?

FNH is one of the benign lesions of the liver, and is seen more often in women.

In most patients it causes no complaint and is found by chance.

Contrast MR is very valuable in distinguishing FNH from other liver lesions.

Where a typical FNH has been diagnosed with certainty on imaging, treatment is not needed in most patients.

FNH is not expected to turn into cancer.

What is a hepatocellular adenoma?

A hepatocellular adenoma is a benign liver tumour, but unlike a haemangioma or FNH it needs to be assessed more carefully.

This is because some adenomas may carry a risk of:

• Growth,
• Bleeding,
• Rarely, malignant change.

It can be associated with the use of oestrogen-containing hormones in women, the use of anabolic steroids in men, and certain metabolic factors.

The size of the adenoma, whether it has grown, the patient’s sex and the characteristics of the lesion all matter in the decision on treatment.

For this reason, being “benign” does not mean that every hepatocellular adenoma can simply be forgotten about.

What is a simple liver cyst?

Liver cysts are very common.

A simple cyst is a fluid-filled and generally entirely benign structure.

A typical simple cyst:

• Has a thin, smooth wall,
• Contains no solid part,
• Mostly causes no symptoms.

Treatment is mostly not needed for simple liver cysts with typical features that cause no complaints.

But where there is thickening of the wall, septations, a nodular structure or other atypical features, further investigation may be needed.

Could it be liver cancer (HCC)?

Yes, but the risk is not the same in everyone.

Hepatocellular carcinoma (HCC) develops particularly on the background of cirrhosis and certain chronic liver diseases.

Newly found liver nodules are assessed more carefully in people with:

• Cirrhosis,
• Chronic hepatitis B,
• Certain chronic liver diseases.

In these patients, the pattern of contrast enhancement of the lesion on contrast CT or MR is very important in making the diagnosis.

What does metastasis mean?

Metastasis is the spread to the liver of a cancer that began in another organ.

Certain cancers in organs such as:

• The large bowel,
• The pancreas,
• The stomach,
• The breast,
• The lung

can spread to the liver.

But seeing a single liver lesion on imaging does not on its own mean it is a metastasis.

Whether the patient has had cancer before is therefore extremely important in the assessment.

Is ultrasound enough?

In some lesions, ultrasound can show quite characteristic findings.

But where ultrasound cannot establish with certainty what the lesion is, more detailed imaging is generally needed.

Contrast MR of the liver or multiphase contrast CT may then be used in particular.

In the current approach, multiphase contrast MR or CT is among the basic investigations for characterising focal liver lesions of uncertain cause.

Why does MR matter?

Liver lesions have different vascular structures and different cellular characteristics.

After contrast is given, how the lesion behaves through:

the arterial phase → the portal venous phase → the late phase

can be examined.

In some situations, liver MR with hepatobiliary contrast agents can be particularly helpful in distinguishing lesions such as FNH from hepatocellular adenoma.

For this reason it is not only the diameter of the lesion in the report that matters but its enhancement characteristics too.

Are blood tests done?

Depending on the patient’s situation, the following may be requested:

• ALT and AST,
• ALP and GGT,
• Bilirubin,
• Albumin,
• INR,
• A full blood count,
• Hepatitis B and hepatitis C tests.

Depending on the condition suspected, tumour markers such as AFP, CA 19-9 or CEA may also be used.

But there is an important point:

Tumour markers do not on their own establish a diagnosis of cancer, nor do they definitely exclude it.

The results must be assessed together with the imaging and the patient’s clinical features.

Is every liver lesion biopsied?

No.

This is one of the things patients most often wonder about.

Modern imaging methods can characterise many liver lesions without a biopsy.

A biopsy is mostly not needed in typical lesions such as:

• A haemangioma,
• FNH,
• A simple cyst.

Indeed, where a typical haemangioma is suspected, a biopsy may be specifically avoided because of the risk of bleeding.

A biopsy comes into consideration where the diagnosis cannot be established with imaging and where the result would change the patient’s treatment.

Does the size of the lesion matter?

Yes, but size alone does not show whether it is benign or malignant.

A large haemangioma can be entirely benign, while a smaller lesion may need further investigation because of its other features.

For this reason:

size + shape + margins + enhancement characteristics + change over time + the patient’s risk factors

should be assessed together.

Why are older images so valuable?

When a new lesion is found in the liver, having the patient’s older ultrasound, CT or MR images can be very useful.

That a lesion has been the same size with the same features for years, for instance, gives important information for the assessment.

For this reason older imaging discs and reports should be shown to the doctor where possible.

In which situations is more care needed?

More detailed assessment may be needed particularly where there is:

• Cirrhosis,
• A history of hepatitis B or C,
• A previous diagnosis of cancer,
• Growth of the lesion over time,
• Imaging features that are not typical,
• Unexplained weight loss,
• Jaundice,
• Constant or increasing pain.

The important message

Finding a single lesion in the liver on imaging is not a diagnosis of cancer.

Benign lesions such as haemangiomas, simple cysts and FNH are quite common, and most need no treatment.

Even so, not every lesion is the same.

The most important questions in the assessment are:

• Does the patient have chronic liver disease?
• Is there a previous history of cancer?
• What are the imaging characteristics of the lesion?
• Is it growing compared with earlier investigations?

Where necessary, the lesion can be characterised in detail with contrast liver MR or multiphase CT. A biopsy is not a procedure carried out routinely in every patient.

This content has been prepared for general information. Assessment of a lesion found in the liver should be made by considering the patient’s age, their liver diseases, any history of cancer, their laboratory results and the imaging characteristics together.