Liver lesions are abnormal growths or areas of tissue within the liver. While their discovery can be concerning, many are non-cancerous, or benign. Benign lesions typically do not spread and often do not cause health problems.
What Are Liver Lesions?
A liver lesion may be referred to as a mass or tumor. These lesions are categorized as either benign (non-cancerous) or malignant (cancerous). Benign lesions are not harmful and often do not require treatment unless they become very large or cause symptoms.
Common benign liver lesions include hemangiomas, which are masses of abnormal blood vessels and are the most frequent type. Focal nodular hyperplasia (FNH) is another common benign lesion, characterized by a mass of abnormal cells due to increased blood flow. Liver adenomas are benign tumors that form near the liver’s surface, while liver cysts are fluid-filled sacs. Malignant lesions require medical intervention to prevent their spread.
How Common Are Liver Lesions?
Liver lesions are common, with many individuals discovering them incidentally during imaging tests for unrelated health issues. Incidental liver lesions have been reported in 10% to 33% of imaging studies, and over 50% of autopsy cases. This high prevalence is partly due to advancements in imaging technologies, such as ultrasounds, CT scans, and MRIs, which detect these abnormalities more readily.
The frequency of incidental liver lesions increases with age. For instance, they are estimated to affect approximately 30% of patients over 40 on cross-sectional imaging. In low-risk patients—those without a history of cancer or chronic liver disease, especially individuals under 40—more than 95% of incidentally found focal liver lesions are likely benign.
Differentiating Benign from Malignant Lesions
Distinguishing between benign and malignant liver lesions is an important step to ensure proper patient care and avoid unnecessary interventions. Doctors consider several factors, including medical history, symptoms, and characteristics observed in imaging studies. While benign lesions often cause no symptoms, malignant ones might lead to abdominal pain, jaundice, or unexplained weight loss.
Imaging techniques such as ultrasound, CT scans, and MRI are primary tools used to examine liver lesions. Each modality provides unique insights into the lesion’s appearance, including size, shape, and internal consistency. For example, hemangiomas often show a distinctive enhancement pattern after intravenous contrast medium, characterized by sequential opacification from the periphery to the center. A peripheral washout on delayed images is a characteristic finding of malignancy, seen in certain liver cancers and metastases.
In some cases, a liver biopsy, which involves taking a small tissue sample, may be necessary to confirm the diagnosis, especially if imaging findings are inconclusive. This is particularly true when differentiating certain benign lesions, like focal nodular hyperplasia, from malignant ones like fibrolamellar hepatocellular carcinoma, as they can share similar imaging features. The goal is to identify the lesion’s nature to guide appropriate management.
Diagnosis and Monitoring
Once a liver lesion is identified, a structured approach involving various medical professionals helps determine the next steps. Radiologists play a central role in interpreting imaging scans to characterize the lesion’s features, often in consultation with gastroenterologists or hepatologists. The initial diagnosis often relies on imaging, with MRI, especially with hepatobiliary-specific contrast agents, proving effective in characterizing focal liver lesions and potentially reducing the need for biopsies.
For many benign lesions, such as simple liver cysts or hemangiomas, no specific treatment or ongoing monitoring may be required, particularly if they are small and asymptomatic. However, certain benign lesions, like hepatic adenomas, may warrant regular follow-up imaging, typically every 6-12 months, to monitor for any changes. If a benign lesion grows significantly or causes symptoms, interventions such as surgical removal might be considered. The overall management strategy aims to balance the benefits of further evaluation against the potential risks and costs of unnecessary procedures.