Benign liver lesions and cysts – something or nothing?



I wanted to focus on two terms “lesion” and “cyst” given these are mentioned all the time in my online patient group, on many occasions by a worried newly diagnosed patient who has just been told (or read before an appointment) this was found during diagnostic scans.  Sometimes these are described by doctors as “liver lesions“. 

Lesion is defined as “An area of abnormal tissue. A lesion may be benign (not cancer) or malignant (cancer)”.  The majority of liver lesions are noncancerous (benign) and will not be related to Neuroendocrine Cancer. Many lesions are detected during imaging tests for unrelated health conditions. Although most lesions aren’t harmful, it’s still critical to receive a proper diagnosis.  This is particularly important if these lesions are in addition to known cancerous ones included with a cancer diagnosis.

Cyst versus Lesion. A radiologist might use the term liberally, but some will distinguish them as one of either if that is clearly shown. Specialist doctors are more likely to distinguish them based on their physical characteristics. 

Malignant liver lesions, either primary liver cancer or secondary liver cancer are beyond the scope of this article, including cancerous cystic tumours.  I have already written about my own liver metastases, including my surgery and liver-directed therapy.

Liver cysts

A cyst is an abnormal, fluid-filled balloon or bubblelike structure (sac) that can grow in any part of your body. Liver cysts are mostly congenital, meaning that you have them from birth.  Less commonly they can be caused by contact with a form of parasite. Others form part of cystic liver disease.  There are around 6 different types of liver cysts ranging from simple cysts to more complex cysts related to liver disease.  Other than what I mentioned here, it looks like doctors don’t really know what causes cysts.

Incidence:  According to Cleveland Clinic, around 15% to 18% of people in the United States and 5% to 10% of people worldwide have liver cysts.

Benign liver tumours

Benign liver tumours are common and usually without symptoms (asymptomatic). They tend to be found during imaging tests for unrelated conditions and, although most need no treatment, it is important for doctors to tell these tumours apart from those that are malignant, particularly in a diagnosed cancer patient for peace of mind.

There are 3 main types of benign liver tumours listed below in order of how common they are. These lesions occur for a variety of reasons and are typically not cause for concern.  More in the types of info below.

– Haemangiomas

Haemangiomas are the most common of all benign solid tumours. Haemangiomas are made up of newly formed but abnormal blood vessels. They can vary in size but are usually less than 5cm (or a couple of inches) and usually remain so once grown. Haemangiomas are usually picked up on ultrasound scanning. Further imaging techniques such as computed tomography (CT) and/or magnetic resonance imaging (MRI) may be required to confirm the diagnosis.

The majority of haemangiomas do not require long-term monitoring or treatment. In rare cases where a tumour becomes overly large, embolisation (a type of treatment aimed at reducing the blood supply to the tumour) and surgery are most commonly used to reduce or remove it.

Incidence. According to UPMC Center for Liver Diseases, between 1% and 5% of people in the U.S. have a liver or hepatic hemangioma that doesn’t cause symptoms

– Focal nodular hyperplasia (FNH)

After haemangiomas, FNH is the most frequent of the benign solid liver tumours. It is commonly found in women aged between 15 and 50. The typical tumour is a small mass or lump commonly measuring between 3cm to 5cm in diameter and is usually found singly. It is characterised by a pale-coloured central scar that in most cases can be seen in CT and MRI scans.

Some people experience pain in their abdomen (the ‘tummy’ or ‘belly’ area between the chest and pelvis) but most do not have clear symptoms. These tumours do not rupture or become malignant and do not need specific treatment.

Incidence.  According to UPMC Center for Liver Diseases, FNH is more common in women, mostly between the ages of 20 and 50. It’s the 2nd most common type of benign liver tumour (liver hemangiomas are the most common). FNH affects between 0.6% and 3% of the general U.S. population. About 8% of all benign liver tumours that aren’t hemangiomas are FNH.

– Liver Adenomas

Hepatic adenomas, also known as hepatocellular adenomas, are rare but benign epithelial tumors of the liver frequently associated with women of reproductive age who are taking exogenous estrogens in the form of oral contraceptive pills. They are also seen in patients treated with anabolic steroids for athletic enhancement, Fanconi anemia, or aplastic anemia. Although benign, they are associated with risks of hemorrhage and malignant transformation.  If these adenomas become malignant this is normally associated with primary liver cancer (Hepatocellular carcinoma (HCC)) rather than a primary or secondary cancer in a Neuroendocrine Cancer patient.  I include this section for completeness only.

Evaluating a Liver Lesion/Cyst

Radiologists are trained to differentiate liver cysts and liver lesions to identify the type, with many of them seeing these lesions almost daily. Clearly, in a diagnosed cancer patient, some benign issues will have been incidentally found during diagnostic workups and some will be labeled for routine monitoring alongside cancer surveillance.  If you have concerns about these cysts and benign lesions, here are some questions you could ask your doctor.

Questions to Ask Your Doctor (Cysts)

  • How do I know whether my cyst is benign or cancerous?
  • Have you seen many other patients with this particular condition?
  • Will I need to have a liver biopsy performed?
  • What kinds of scans are needed?
  • Can a cyst be removed if it is causing me discomfort?
  • If my cysts need to be removed, is there a specific specialist that I should be referred to?
  • Will my cyst be monitored to check on its size and location over a period of time?
  • If I have liver cysts, should I get other kinds of testing to check for cysts anywhere else in my body?

Questions to Ask Your Doctor (Benign liver lesions)

  • What kind of benign liver tumour do I have? (Hemangioma, Focal nodular hyperplasia or Hepatocellular adenoma)
  • Do I need to do further imaging studies to access the size?
  • Will there be repeat imaging studies to monitor the issue?
  • Will a biopsy be needed to look at the tissue?
  • Should the tumours be removed?
  • (If needed to be removed), what kind of specialist should I follow up with? A surgeon?
  • Do I need to do other kinds of cancer screenings such as a blood test or a PET scan?
  • Is it possible for the tumours to be causing discomfort?


Clearly, when you already have a cancer diagnosis, the discovery of more issues on top of that is of concern to patients and their families. As inferred above, many are incidental and only found because of imaging during an investigation of something else, e.g. a cancer diagnosis.  But it’s really important to remember that most liver lesions aren’t cancerous and most will not require treatment.  There are no benefits to treating a cyst or other benign lesion that is causing you no harm, and there could be more risk from any treatment. For example, it is perfectly possible that I have had a simple cyst since I was born (decades!) and it had caused me no problems. I hope this has been useful for those who have been told they have a benign liver lesion.  It would seem for most; this is a minor and low-risk issue. 

I’m aware from some comments that people have been told they had a benign issue, and this was something later removed but unless it was biopsied and found to be cancerous, it may have been an opportunistic removal during surgery for known cancerous lesions/tumours. 

Reminder.  Above, I said malignant liver lesions are beyond the scope of this blog. 

References Used/Further Reading

1.  British Liver Trust (cysts) – click here

2. Cleveland Clinic – click here

3.  UPMC – click here

4. American Liver Foundation.  Click here and here

Also in my “Something or Nothing” series:

Click on the picture to read
Click on the picture to read


I am not a doctor or any form of medical professional, practitioner or counsellor. None of the information on my website, or linked to my website(s), or conveyed by me on any social media or presentation, should be interpreted as medical advice given or advised by me. 

Neither should any post or comment made by a follower or member of my private group be assumed to be medical advice, even if that person is a healthcare professional.   

Please also note that mention of a clinical service, trial/study or therapy does not constitute an endorsement of that service, trial/study or therapy by Ronny Allan, the information is provided for education and awareness purposes and/or related to Ronny Allan’s own patient experience. This element of the disclaimer includes any complementary medicine, non-prescription over the counter drugs and supplements such as vitamins and minerals.

Thanks for reading.


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