Biliary Adenoma

Biliary adenoma is a rare, noncancerous growth that develops from the cells that line the bile ducts inside or near the liver. These small tumors are usually discovered by accident during surgery or imaging tests for other reasons, and while they generally don’t cause problems, they require careful evaluation to distinguish them from more serious conditions.

Table of contents

• What Is Biliary Adenoma?
• Alternative Names
• Signs and Symptoms
• Who Can Develop This Condition?
• How Is It Diagnosed?
• Cancer Risk and Complications
• Treatment Options

What Is Biliary Adenoma?

Biliary adenoma is a benign tumor, meaning it is not cancerous, that grows from the cells that line the bile ducts. Bile ducts are small tubes that carry bile, a digestive fluid made by your liver and stored in your gallbladder, through your body to help digest food^[1]. These tumors are found in your liver or just outside of it.

This condition is extremely rare. Studies suggest that biliary adenomas represent only about 0.5 to 2% of all liver tumors^[2]. Because they are so uncommon and often cause no symptoms, many cases are discovered only during surgery performed for other reasons or during autopsy examinations^[2][3].

Under the microscope, biliary adenomas show a distinct pattern. They consist of a growth of small, uniform bile duct structures embedded in fibrous tissue. The cells appear normal with minimal abnormal features and no signs of rapid division^[2]. The tumor is well-defined and separate from the surrounding liver tissue, though it typically has no outer capsule^[2].

peribiliary gland hamartomas, bile duct adenoma, BDA

Alternative Names

Biliary adenomas are sometimes called by other names in medical literature. The term peribiliary gland hamartoma is used by some doctors who believe these growths may be developmental abnormalities rather than true tumors^[1][2]. You may also see the condition referred to simply as bile duct adenoma or abbreviated as BDA.

Signs and Symptoms

Most people with biliary adenoma have no symptoms at all. These tumors are typically very small, usually measuring between 1 and 20 millimeters (about the size of a pea or smaller)^[1]. Because of their small size and location inside the liver, they usually remain undetected until discovered accidentally^[1].

When symptoms do occur, they may include:

• Jaundice, which is yellowing of your skin and the whites of your eyes
• Pain around your liver or small intestine that comes and goes, typically felt just under your ribs on the right side
• Unexplained weight loss
• Indigestion
• Nausea and vomiting
• Fever

These symptoms are more likely to appear if the tumor grows larger or if complications develop^[1].

Who Can Develop This Condition?

Biliary adenoma can occur at any age, with cases reported in both children and adults. There is no significant difference in occurrence between men and women^[2]. Most cases are discovered in people between 20 and 70 years old, with the average age being around 55 years^[5].

The exact cause of biliary adenoma remains unclear. Some experts debate whether these growths are true tumors or developmental abnormalities. Some suggest they may be a response to a specific, self-limited injury to the liver tissue^[2].

• Liver
• Bile ducts

How Is It Diagnosed?

Diagnosing biliary adenoma presents challenges because these tumors often have no specific features on imaging tests that would clearly identify them. Most cases are found incidentally during imaging scans or surgery performed for other medical reasons^[2][3].

When a liver nodule is discovered on imaging, doctors may use several tests to investigate further. CT scans (computed tomography) or MRI scans (magnetic resonance imaging) can show the tumor in detail, but the images may look similar to other types of liver growths, including cancerous ones^[5]. No blood tests or tumor markers can definitively identify biliary adenoma before surgery^[2].

The only way to make a definitive diagnosis is through examination of the tissue under a microscope. This may happen during a biopsy, where a small sample of tissue is removed for testing, or after surgical removal of the tumor^[2][3]. During surgery, doctors may perform a rapid analysis called a frozen section to help guide their decisions during the procedure^[2].

Cancer Risk and Complications

Most of the time, biliary adenomas don’t pose a serious health threat. The risk that these tumors will grow larger or become malignant (cancerous) is considered low^[1]. However, there are some important considerations.

Biliary adenomas may sometimes develop as a step before bile duct cancer, though this is uncommon. Bile duct cancer itself is rare, and there is no standard screening test to check for it^[1]. When biliary adenomas occur in the common bile duct (the main tube that carries bile from the liver), they carry a higher risk of progressing to cholangiocarcinoma (bile duct cancer). This progression can occur through activation of cancer-causing pathways^[4].

There is also a possibility that biliary adenomas may grow large enough to become painful or uncomfortable. If this happens, your doctor may recommend removal^[1].

One challenge in managing these tumors is that doctors often cannot easily distinguish a benign tumor from a cancerous one based on imaging scans alone, as they may appear similar. However, finding multiple tumors or very large tumors may suggest cancer rather than benign adenoma^[1].

Treatment Options

Treatment decisions for biliary adenoma depend on several factors, including the size and location of the tumor, whether it causes symptoms, and the risk of complications.

For small biliary adenomas that cause no symptoms, doctors may recommend careful monitoring rather than immediate treatment. This approach, called “watchful waiting,” involves regular imaging scans to check if the tumor grows or changes^[2].

When treatment is needed, the main option is surgical removal. The type of surgery depends on where the tumor is located and how large it has grown. Options include:

Liver resection involves removing the portion of the liver containing the tumor along with a margin of healthy tissue around it. This is often recommended for larger tumors or when cancer cannot be ruled out^[3][5].

Enucleation is a procedure where the tumor is carefully removed while preserving as much healthy liver tissue as possible. This may be appropriate for smaller, well-defined tumors^[2].

In one reported case, a patient underwent complete removal of a biliary adenoma along with surrounding tissue, with the entire mass removed through a margin of 2 centimeters around it. The patient recovered well with no complications or recurrence^[3].

For tumors located in the common bile duct, more aggressive treatment is often recommended due to the higher risk of cancer development. This is particularly true for adenomatous growths in this location, which require early and thorough treatment^[4].

After successful treatment, patients typically require follow-up monitoring to ensure the tumor does not return and to watch for any new growths.