Liver tumors are growths of cells that develop in the liver. These growths can be either benign (non-cancerous) or malignant (cancerous). Many people have benign liver growths that pose little threat to their health.
Prevalence of Benign Liver Tumors
Benign liver tumors are more common than malignant ones. Around 70% of all liver lesions identified are benign, while about 30% are malignant. Up to 9% of the population may have benign liver nodules. Hemangiomas are found in 1% to 5% of adults. Even in individuals diagnosed with cancer elsewhere in the body, a significant proportion, between 25% and 50%, of liver changes are benign. These statistics highlight that discovering a liver lesion does not automatically mean a cancer diagnosis.
Common Benign Liver Tumor Types
Several types of benign liver tumors exist, including hemangiomas, focal nodular hyperplasia (FNH), and hepatocellular adenomas. Hemangiomas, the most common type, consist of tangled clumps of blood vessels. They are often small, typically less than 5 centimeters, and usually do not cause symptoms. Many individuals are unaware they have them, as they are often discovered incidentally during imaging for other conditions.
Focal nodular hyperplasia is the second most common type. These growths are characterized by an abnormal arrangement of liver cells, often with a central scar. FNH lesions are typically asymptomatic, rarely grow or bleed, and are generally discovered incidentally.
Hepatocellular adenomas are less common, typically occurring in women of childbearing age. These tumors are growths of liver cells that lack normal liver architecture. While often asymptomatic, they carry a small risk of bleeding and, rarely, can transform into a malignant tumor.
Distinguishing Benign from Malignant
Distinguishing benign from malignant liver tumors is essential for proper management. Healthcare providers use several diagnostic methods. Imaging techniques are primary tools, including ultrasound, computed tomography (CT) scans, and magnetic resonance imaging (MRI). These modalities provide detailed pictures of the liver, revealing tumor characteristics like size, shape, and internal structure.
MRI, particularly with specialized contrast agents, is often preferred for evaluating liver tumors due to its ability to help differentiate between various types of lesions. In some cases, the appearance of a tumor on CT or MRI scans can be enough to confidently diagnose it as benign or malignant without further invasive procedures. When imaging results are inconclusive or if there is suspicion of malignancy, a liver biopsy may be performed. This procedure involves taking a small tissue sample from the tumor for examination under a microscope, which can provide a definitive diagnosis. However, biopsies are generally avoided for suspected hemangiomas due to a small risk of bleeding.
Management of Benign Liver Tumors
The management of benign liver tumors depends on the specific type of tumor, its size, and whether it causes symptoms. Most benign liver tumors, particularly hemangiomas and many focal nodular hyperplasias, do not require active treatment. They are often discovered incidentally and remain asymptomatic, with little to no risk of becoming cancerous. In such cases, the usual approach involves observation and periodic monitoring with imaging to ensure the tumor does not grow or change.
Intervention may be considered if a benign tumor grows significantly, causes symptoms like pain or discomfort, or if there is uncertainty about the diagnosis. For hepatocellular adenomas, surgical removal is often recommended due to the potential for bleeding or malignant transformation, especially if they are larger than 5 cm or found in men. Surgical options for benign tumors include traditional or minimally invasive approaches, depending on the tumor’s characteristics and location. Other non-surgical treatments like radiofrequency ablation or embolization are occasionally used for symptomatic hemangiomas.