A mass on the liver refers to an abnormal growth, also called a lesion or tumor, that develops either on its surface or within its tissue. While discovering a liver mass can cause concern, not all masses are cancerous. Many are benign and generally do not pose a serious health risk. Understanding the nature of a liver mass, whether benign or malignant, is fundamental to determining its significance.
Understanding Liver Masses: Benign vs. Malignant
The distinction between benign (non-cancerous) and malignant (cancerous) liver masses is important. Benign masses do not spread to other parts of the body and rarely become cancerous. Malignant masses, however, are cancerous growths that can invade surrounding tissues and spread to distant organs.
Common types of benign liver masses include hemangiomas, focal nodular hyperplasia (FNH), and hepatic adenomas. Hemangiomas are the most frequent type, consisting of abnormal blood vessels, often causing no symptoms. FNH represents an overgrowth of liver cells around an abnormal artery, and is more common in women. Hepatic adenomas are less common benign tumors, linked to hormonal influences, particularly in women using oral contraceptives, and while generally harmless, some may carry a risk of rupture.
Malignant liver masses are categorized into primary liver cancer and metastatic liver cancer. Primary liver cancer originates within the liver itself, with hepatocellular carcinoma (HCC) being the most common type. HCC often develops in individuals with chronic liver disease, such as cirrhosis. Metastatic liver cancer occurs when cancer cells from another part of the body spread to the liver. This means the liver mass is a secondary tumor, retaining the characteristics of the original cancer.
Common Causes of Liver Masses
The development of liver masses stems from various factors, differing between benign and malignant types. For many benign masses, such as hemangiomas and FNH, there is often no clear cause. Some benign masses, like hepatic adenomas, have been linked to hormonal influences. Genetic predispositions and certain inherited conditions can also increase the likelihood of developing some benign liver tumors.
In contrast, malignant liver masses, particularly primary liver cancers like HCC, are strongly associated with specific risk factors. Chronic viral hepatitis is a significant cause worldwide. Cirrhosis, a severe scarring of the liver often resulting from chronic liver diseases, is a major underlying factor for HCC development. Excessive alcohol consumption, obesity, and diabetes are also contributing factors that can lead to liver damage and increase the risk of malignant masses.
How Liver Masses Are Detected and Diagnosed
Many liver masses are discovered incidentally during imaging tests performed for unrelated health conditions. This is because most liver masses often do not cause noticeable symptoms. When symptoms do occur, they can be non-specific and might include abdominal pain, a feeling of fullness, nausea, unexplained weight loss, fatigue, or yellowing of the skin and eyes (jaundice).
Diagnostic methods typically begin with imaging techniques. Ultrasound is often the first step, as it can differentiate between fluid-filled cysts and solid masses. More detailed imaging, such as CT and MRI scans, are then used to further characterize the mass, providing information on its size, shape, location, and blood supply. MRI is preferred for its ability to image soft tissue and provide high contrast.
Blood tests can also provide valuable clues, evaluating liver function and checking for tumor markers, which can be elevated in some liver cancers. If imaging and blood tests are inconclusive, or if malignancy is strongly suspected, a liver biopsy may be necessary. This involves taking a small tissue sample from the mass for microscopic examination to confirm the diagnosis.
Treatment Approaches for Liver Masses
Treatment for a liver mass is highly individualized and depends on several factors, including the type of mass (benign or malignant), its size, location, the patient’s overall health, and the extent of liver function. For many benign liver masses, no treatment is required. Instead, these masses are monitored with periodic imaging to ensure they do not grow significantly or cause symptoms. If a benign mass becomes very large or causes discomfort, surgical removal might be considered.
For malignant liver masses, a range of treatment modalities is available. Surgical removal, known as resection, is a common approach for localized tumors, where a portion of the liver containing the mass is removed. In some cases, a liver transplant may be an option, replacing the diseased liver with a healthy one.
Localized therapies aim to destroy cancer cells directly within the liver. These include radiofrequency ablation (RFA) and microwave ablation (MWA), which use heat or energy to destroy tumor cells. Transarterial chemoembolization (TACE) involves delivering chemotherapy drugs directly to the tumor through the hepatic artery, followed by blocking its blood supply. Other localized treatments include transarterial radioembolization (TARE) and percutaneous ethanol injection (PEI).
Systemic therapies are used when the cancer is more widespread or cannot be treated with localized approaches. These treatments circulate throughout the body to target cancer cells. They include chemotherapy, targeted therapy drugs that block specific pathways involved in cancer growth, and immunotherapy, which boosts the body’s immune response against cancer. Treatment plans are determined by a multidisciplinary team of specialists to ensure the most effective and personalized approach.