A liver mass is an abnormal growth or lesion found within the liver. While discovering a mass can cause concern, many liver masses are not cancerous and do not pose an immediate threat. A medical evaluation is always necessary to determine its specific nature.
Understanding Liver Masses
Liver masses represent a diverse group of growths. These masses are frequently discovered incidentally, meaning they are found during imaging tests, such as an ultrasound or CT scan, performed for unrelated health concerns. Sometimes, however, a liver mass might cause vague symptoms like a feeling of fullness or discomfort in the upper right abdomen, or in rarer cases, unexplained weight loss. All liver masses generally fall into one of two broad categories: benign (non-cancerous) or malignant (cancerous).
Common Benign Liver Masses
Many liver masses are benign and typically do not spread to other parts of the body. These types of masses often require no treatment beyond careful monitoring. One of the most common types is a hemangioma, which is a tangle of blood vessels that forms a benign tumor. These are often present from birth and usually cause no symptoms.
Another common benign liver mass is focal nodular hyperplasia (FNH), which is a tumor-like lesion that develops as an abnormal response to blood flow within the liver. FNH lesions are generally asymptomatic and rarely cause complications, often remaining stable over time. Liver cysts are also frequently found and consist of fluid-filled sacs within the liver tissue. These cysts are harmless and do not require intervention unless they grow large enough to cause symptoms like pain or pressure.
Liver adenomas are a rarer type of benign liver tumor, sometimes linked to the use of oral contraceptives or anabolic steroids. Adenomas carry a small risk of complications, including bleeding or, rarely, transforming into a malignant tumor. Because of these potential risks, liver adenomas may require more careful monitoring or even surgical removal, depending on their size and location.
Malignant Liver Masses
Malignant liver masses indicate cancer. These can be broadly divided into primary liver cancer, which originates within the liver, and metastatic liver cancer, which spreads to the liver from another part of the body. Primary liver cancer is less common than metastatic liver cancer.
The most prevalent type of primary liver cancer is hepatocellular carcinoma (HCC), which typically develops in individuals with chronic liver diseases such as cirrhosis, often caused by hepatitis B or C infections, or chronic alcohol abuse. Another form of primary liver cancer is cholangiocarcinoma, which arises from the bile ducts within or outside the liver. This type of cancer is less common than HCC and can be more challenging to diagnose early. Both HCC and cholangiocarcinoma can present with symptoms like unexplained weight loss, abdominal pain, or jaundice.
Metastatic liver cancer occurs when cancer cells from a tumor elsewhere in the body travel through the bloodstream or lymphatic system and establish new tumors in the liver. The liver is a common site for metastasis due to its rich blood supply. Cancers that frequently spread to the liver include those originating in the colon, rectum, lung, breast, and pancreas. The presence of metastatic lesions in the liver usually indicates a more advanced stage of the original cancer.
Diagnosis and Evaluation of Liver Masses
Determining the nature of a liver mass involves a comprehensive diagnostic process. Imaging studies are typically the first step, providing pictures of the liver and any abnormalities. Common imaging techniques include ultrasound, which uses sound waves to create images, and computed tomography (CT) scans, which use X-rays to produce cross-sectional images. Magnetic resonance imaging (MRI) provides even more detailed images using magnetic fields and radio waves, and can often help differentiate between various types of masses based on their unique characteristics.
Blood tests also play a supportive role in evaluating liver masses. Liver function tests can indicate the overall health of the liver, while specific tumor markers, such as alpha-fetoprotein (AFP) for hepatocellular carcinoma, can provide additional clues. Tumor markers are not definitive diagnostic tools, as elevated levels can occur in non-cancerous conditions, and normal levels do not rule out cancer.
When imaging and blood tests are inconclusive, a liver biopsy is often performed to obtain a definitive diagnosis. This procedure involves taking a small tissue sample from the mass, which is then examined under a microscope by a pathologist. A biopsy provides the most accurate information about the cell type and whether the mass is benign or malignant. Only a medical professional can accurately interpret these test results and determine the appropriate course of action, which may include monitoring, further investigation, or treatment.