Focal Nodular Hyperplasia

Overview

Focal nodular hyperplasia (FNH) is a harmless growth that can form in the liver. The name sounds complicated, but it simply describes a small patch of liver tissue that has grown in a slightly jumbled way, like a knot inside the liver. It is made of normal liver cells — just arranged differently — and it is not cancer. It does not spread to other parts of the body, and it does not turn into cancer over time. Most people who have FNH never know it, and many never need any treatment at all.

Yes, it is one of the more common harmless liver growths. Studies suggest it may be present in around 1 to 3 in every 100 adults, and probably more, since many people never have a scan that would find it. It is the second most common benign liver tumour after haemangioma (a harmless collection of blood vessels).

FNH is much more common in women than in men, and it is usually found in women of childbearing age, roughly between 20 and 40 years old. It can happen in men and in children, but this is rare. It is not linked to any particular ethnicity or background, and it is not caused by anything you did or did not do.

Symptoms

Common symptoms

• No symptoms at all in most people — it is usually found by chance on a scan
• A mild ache or feeling of fullness in the upper right part of the tummy
• Occasional discomfort after eating or when lying on the right side
• A sense of bloating or a mild 'heavy' feeling in the belly

Symptoms in children

• FNH is very rare in children and is usually completely silent
• When found, it is almost always discovered during scans done for other reasons
• If a child has tummy pain, it is far more likely to have a common cause such as constipation or a tummy bug — but always ask a doctor if you are worried

Symptoms in older adults

• FNH is often found in later life during scans for unrelated health checks
• Symptoms, if any, are much the same as in younger adults — mild ache or fullness
• Because other liver conditions are more common with age, doctors may do extra checks to be sure of the diagnosis

Causes

Main causes

• The exact cause is not fully understood. Experts believe FNH happens when the liver grows extra tissue around a small, unusually formed blood vessel — a kind of local overgrowth in response to changes in blood flow.
• It is not an infection, and it is not contagious.
• It is not caused by alcohol, diet, smoking, stress, or any lifestyle choice.
• It is not inherited in a predictable way, though family patterns are occasionally seen.

Risk factors

• Being a woman of childbearing age — by far the strongest factor
• Taking combined hormonal contraception for a long time — this may be linked to growth of the lesion, but it is not proven to cause it
• Pregnancy may make an existing FNH more noticeable, though this is uncommon
• Certain rare blood vessel conditions have been reported alongside FNH in a small number of cases

When to see a doctor

See a doctor urgently if:

• Severe or worsening pain in the upper right tummy
• Pain with fever, chills, or feeling generally very unwell
• Yellowing of the eyes or skin
• Vomiting blood or passing black tarry stools — call emergency services
• Feeling faint, dizzy, or collapsing

Book a routine appointment if:

• You have been told about an FNH on a scan and want to understand what it means
• You have mild, ongoing tummy discomfort that you would like checked
• You are planning a pregnancy and want to talk about your liver growth
• You are thinking about starting, stopping, or changing hormonal contraception
• You have new symptoms and are not sure whether they are related

Diagnosis

FNH is usually found by chance, when someone has a scan of their tummy for a completely different reason. Once it is spotted, the main job is to confirm what it is and rule out other liver growths that need more attention. In most cases this can be done with a specialised scan, and a biopsy (a small sample of tissue) is rarely needed.

Tests that may be done

• Blood tests to check how your liver is working and to look for other conditions
• Ultrasound scan of the tummy — often the first test
• CT scan (a detailed 3D X-ray) with contrast dye to show how the growth behaves
• MRI scan, especially with a liver-specific contrast dye — this is often the most accurate way to confirm FNH without surgery
• Sometimes a biopsy, where a tiny sample of the growth is taken with a needle and looked at under a microscope — used only when the scans are unclear
• Sometimes repeat scans some months later to check the growth is stable

What to expect at your appointment

You will usually be referred to a liver specialist (hepatologist) or a specialist liver team. There may be a short wait for scans and results, which can feel anxious. The specialist will look at your images, sometimes with a radiologist, and decide whether the diagnosis is clear. If it is clear, you may be offered a follow-up scan in a few months and then no further tests. If the picture is uncertain, you may be offered more imaging or, rarely, a biopsy. Ask questions at every step — you are entitled to understand your own results.

Treatment

For most people, the treatment for FNH is simply reassurance and, sometimes, a follow-up scan. Because FNH is harmless and does not become cancer, doctors usually avoid surgery unless there is a clear reason. If you have bothersome symptoms, your doctor will talk through options with you, starting with the gentlest ones.

Self-care at home

• Keep copies of your scan reports and clinic letters in one place, so any new doctor can see your history quickly
• Note down any symptoms, when they happen, and how bad they are — this helps your doctor decide if anything needs to change
• Mention your FNH whenever you fill in a medical history form or see a new healthcare professional
• Stay physically active and keep to a healthy weight — this supports your general liver health
• Keep alcohol within the recommended limits and avoid binge drinking
• Try small, regular meals if a heavy meal makes the fullness feel worse
• Talk to your doctor before starting any new hormonal contraception or hormone treatment
• Attend any follow-up appointments or scans your team recommends

Medical treatments

There are no medicines that make FNH shrink or go away, and none are needed for most people. If you have discomfort, your doctor may discuss simple pain relief and general measures with you, and your pharmacist can advise on what is suitable for you. Because combined hormonal contraception has been linked in some studies to changes in the size of these liver growths, your doctor may talk with you about the pros and cons of your current contraceptive method — this is a personal decision, not an emergency, and there are many alternatives. If you are pregnant or planning a pregnancy, tell your team so they can advise you. Any decisions about medicines should always be made with your own doctor or pharmacist.

When is surgery considered?

Surgery is only considered in a small number of situations. These include: symptoms that are significant and continue despite other measures; uncertainty about the diagnosis after detailed scans; a growth that is enlarging quickly or causing problems; or, very rarely, a complication such as bleeding. If surgery is suggested, it is usually carried out by a specialist liver surgical team, often using keyhole (laparoscopic) techniques, and removes only the affected part of the liver. The remaining liver is healthy and works normally. Your specialist will explain the risks and benefits fully so you can decide together.

Living with this condition

For most people, living with FNH means very little changes. You do not need to avoid activities, foods, or everyday stresses. You may simply have a note on your medical record and, sometimes, a follow-up scan. Some people find the first few months after diagnosis the hardest, because the word 'tumour' plays on their mind — this usually settles once the diagnosis is confirmed by a specialist.

Lifestyle tips

• Keep active in whatever way you enjoy — walking, swimming, cycling, gardening, or anything that gets you moving
• Eat a balanced diet with plenty of vegetables, fruit, wholegrains, and lean protein
• Keep alcohol within your country's recommended limits, and avoid heavy drinking
• Aim for a healthy weight — extra weight around the middle is linked to fatty liver, which is a separate but common issue
• Get enough sleep and find ways to manage stress, such as time outdoors, breathing exercises, or talking to friends
• Do not smoke, and get support to stop if you do

Diet and exercise

There is no special diet for FNH — no food makes it grow and no food makes it shrink. The best approach is simply a heart-and-liver-friendly way of eating: plenty of plants, moderate portions, not too much sugar or processed food, and alcohol in moderation. Regular movement — even 20 to 30 minutes of brisk walking most days — supports liver health and helps with weight, mood, and sleep. If you have other health conditions, ask your doctor or a dietitian for advice that suits you.

Mental health and emotional wellbeing

It is very common to feel anxious after being told you have a growth in your liver. Some people worry about cancer, about the future, or about whether they should exercise or travel. These feelings are understandable and usually ease with good information and time. If worry is affecting your sleep, appetite, work, or mood, please tell your doctor — support such as counselling is available and can help a great deal. You do not have to cope alone.

Prevention

FNH cannot be prevented, and it is not your fault. Nothing you ate, drank, or did caused it. Because it is something you are likely born with or develop without any clear trigger, there is no known way to stop it happening. What you can do is look after your general liver health by eating well, staying active, and keeping alcohol within recommended limits.

Screening programmes

There is no routine screening programme for FNH, and none is needed, because it is harmless. If your specialist recommends a follow-up scan, that is to confirm the diagnosis and check the growth is stable — not because of any cancer risk.

Complications

If left untreated

• In most people, nothing happens — FNH stays the same size or changes very slowly, and causes no problems
• A small number of people have ongoing discomfort or a feeling of fullness
• Very rarely, a large FNH can bleed inside itself, causing sudden pain — this is uncommon and treatable
• There is no known risk of FNH turning into liver cancer
• If a growth is actually a different type of liver lesion that was mistaken for FNH, the correct diagnosis matters — which is why specialists sometimes repeat scans

Long-term outlook

The outlook for FNH is excellent. It is a benign condition, it does not shorten life, and the overwhelming majority of people need no treatment at all. Most people go back to their normal routine after a confirmed diagnosis and a conversation with their doctor. If you do need surgery, the results are generally very good, because the rest of the liver is healthy and works normally. You can live a full, active life with FNH.

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