Hepatic Adenoma

hepatocellular adenoma, liver cell adenoma, HCA

Hepatic adenoma is a rare, non-cancerous liver tumor that primarily affects women, especially those who use birth control pills. Although benign, these tumors carry risks of internal bleeding and, in rare cases, can transform into cancer.

Table of contents

• What is hepatic adenoma?
• Symptoms
• Causes and risk factors
• How is it diagnosed?
• Types of hepatic adenoma
• Complications
• Treatment options
• Where hepatic adenoma affects

What is hepatic adenoma?

Hepatic adenoma is an uncommon, benign (non-cancerous) liver tumor. This means it does not spread to other parts of your body like cancer would^[1]. The tumor starts from liver cells called hepatocytes, which are the main working cells of the liver^[1].

This condition is very rare, occurring in less than 0.007-0.012% of the population^[4]. It happens much more often in women than in men, with a ratio of approximately 10 to 1^[5]. The strong link to women is because hepatic adenoma is closely associated with the use of estrogen-containing birth control pills^[2].

Most people with hepatic adenoma have just one tumor, though some may develop multiple tumors. These growths can range in size from less than 1 centimeter to as large as 30 centimeters^[3]. On average, hepatic adenomas measure between 8 and 15 centimeters^[4].

Symptoms

About half of the time, hepatic adenomas do not cause any symptoms at all. You may not even know you have one^[1]. Many people discover their tumor by accident when they have imaging tests done for unrelated reasons^[7].

When symptoms do occur, they are usually mild and happen when the tumor grows large enough to put pressure on nearby organs. Common symptoms include pain or a feeling of fullness in the right upper part of your abdomen, nausea, or bloating^[1][5].

The most serious problem occurs when a hepatic adenoma ruptures and bleeds. This is a life-threatening emergency that requires immediate medical attention^[1]. Warning signs of rupture include severe belly pain, stomach bloating, vomiting, cold sweats, a rapid pulse, low blood pressure, and signs of internal bleeding^[1][2]. If you experience any of these symptoms, get medical help right away.

Causes and risk factors

Anyone can develop a hepatic adenoma. Changes in your genes, called mutations, may play a role^[1]. However, certain factors significantly increase your chances of developing this condition.

The strongest risk factor is the use of estrogen-based oral contraceptive pills. Your risk increases when you take higher-dose estrogen pills for longer periods of time^[1]. The incidence of hepatic adenomas is as much as 30-40 times higher in women who use oral contraceptives, with an overall incidence estimated at 34 per million in women taking these pills, compared with about 1-1.3 per million in women not taking them^[4].

Pregnancy also increases your risk because your body releases higher levels of sex hormones when you are expecting^[1]. Hepatic adenomas can grow during pregnancy and may be more likely to rupture^[1].

Other medicines and conditions that raise your chances include anabolic steroids (drugs that act like testosterone), clomiphene (a fertility drug), and recombinant human growth hormones used to treat growth disorders^[1]. Barbiturate sedatives have also been linked with hepatic adenoma^[1].

Being overweight, having obesity, or having metabolic syndrome (a cluster of conditions including high blood pressure, high blood sugar, and abnormal cholesterol levels) have been associated with hepatic adenoma, especially in men^[1][2]. Type 1 diabetes and certain genetic diseases called glycogen storage diseases (particularly types I and III) can also affect how your liver works and increase risk^[1][2].

How is it diagnosed?

If your doctor suspects you may have a liver tumor, the first step is usually an imaging test. An ultrasound is often the initial test used because it is simple and non-invasive^[1][7].

If the ultrasound shows that you have a tumor, you will likely need additional imaging tests that provide more detail. These may include a CT scan (computed tomography) or an MRI (magnetic resonance imaging)^[1]. These advanced imaging tests help your doctor confirm that the mass is a hepatic adenoma and provide information about its size and location^[2].

MRI can be particularly helpful because it can often differentiate hepatic adenoma from other types of liver tumors and can sometimes identify specific subtypes of hepatic adenoma^[4].

In some cases, your doctor may need more information about your tumor. A biopsy may be recommended, which is a procedure where a small sample of tissue is removed from the mass and examined under a microscope^[1]. However, biopsy is not always necessary and is typically only done when there is uncertainty in the diagnosis or suspicion that the tumor might be cancerous^[13].

Types of hepatic adenoma

There are four main types of hepatic adenoma. Each type has different characteristics and different risks for complications^[1][4].

Inflammatory hepatic adenomas make up 40-50% of all cases. These are usually found in women and are associated with obesity, alcohol intake, and oral contraceptive use^[4][13]. This type is not associated with an increased risk of turning into cancer.

HNF-1 inactivated adenomas account for 35-40% of all hepatic adenomas. These are almost exclusively found in women and usually do not cause complications^[1][13]. This type is not associated with an increased risk of becoming cancerous.

Beta-catenin activated adenomas make up 15-20% of cases. Men are more likely to get this type of adenoma^[1]. This is the most concerning type because it has a higher risk of transforming into liver cancer^[13].

Unclassified adenomas represent about 10% of hepatic adenomas. These do not fit clearly into the other categories^[1].

The type of hepatic adenoma you have can affect your treatment plan and how closely your doctor needs to monitor you.

Complications

If hepatic adenoma is not treated, two main complications can occur: rupture with bleeding and transformation into cancer.

Rupture and bleeding are more common in larger tumors, particularly those larger than 5 centimeters^[1]. Pregnant women, those who recently took hormones, and those with inflammatory hepatic adenomas have higher chances of experiencing rupture^[1]. When a tumor ruptures, it can bleed heavily into the abdominal cavity, causing severe pain, low blood pressure, and potentially life-threatening shock^[2].

The risk of malignant transformation (turning into cancer) is relatively small but real. About 5% of hepatic adenomas can transform into liver cancer^[1]. This happens more often in men, in patients with larger tumors, and particularly in those with beta-catenin activated adenomas^[1][13].

Because men with hepatic adenoma have a higher risk of the tumor becoming cancerous, the treatment approach for men is often more aggressive than for women^[3][13].

Treatment options

Treatment for hepatic adenoma depends on several factors, including the size of the tumor, whether you are male or female, what type of adenoma you have, and whether you have symptoms.

If you are a woman with a hepatic adenoma smaller than 5 centimeters, medical management with careful monitoring may be appropriate. The first step is typically to stop using oral contraceptives or any other hormones that may have contributed to the tumor’s growth^[10]. In most cases, stopping these medications allows the tumor to shrink in size, although complete disappearance is uncommon^[10][8].

If you are overweight or obese, your doctor will likely recommend weight loss, as this can help reduce the size of the tumor^[10]. You will need regular imaging tests to monitor the tumor. Typically, you will have imaging done at 6 months and 12 months after diagnosis, then annually if the tumor remains stable^[10].

Surgical removal is recommended in several situations. All men with hepatic adenoma should undergo surgery regardless of tumor size because of their higher risk of cancer transformation^[2][13]. Women with tumors larger than 5 centimeters should also have surgery, especially if the tumor does not shrink with lifestyle changes^[10]. Patients with beta-catenin activated adenomas should be referred for removal regardless of tumor size because of the increased cancer risk^[4].

If you have symptoms such as pain, or if your tumor is growing despite stopping hormones and losing weight, surgery may also be recommended.

For patients who cannot undergo traditional surgery, alternative treatments may be considered. These include transarterial embolization (a procedure that blocks blood flow to the tumor) or radiofrequency ablation (using heat to destroy the tumor)^[10].

In rare, complex cases where tumors are very large or multiple, liver transplantation may be considered, though this is not a standard treatment^[12].

Where hepatic adenoma affects

• Liver

The liver is located in the upper right part of your abdomen, just below your diaphragm. Hepatic adenomas can develop anywhere in the liver but are most commonly found in the right lobe^[2]. The tumor develops from hepatocytes, which are the main functional cells of the liver responsible for processing nutrients, removing toxins, and producing important proteins.