A liver lesion is an abnormal area of tissue found within the liver. While patients often immediately think of cancer, the majority of these lesions are non-cancerous, or benign. Benign liver lesions are very common, found in up to 30% of people over age 40, and are frequently discovered incidentally during imaging for unrelated conditions. The primary concern is determining the exact nature of the lesion: whether it is a harmless growth or one that requires intervention.
Non-Cancerous Types of Liver Lesions
Hemangiomas are the most frequent type, consisting of tangles of abnormal blood vessels found in up to 5% of adults. They typically do not cause symptoms and are more common in women. Treatment is rarely required unless they become very large, cause pain, or are at risk of rupture.
Focal nodular hyperplasia (FNH) is the second most common non-cancerous tumor, characterized by a central scar visible on imaging. This growth is made of various cell types, including liver and bile duct cells. Although benign, FNH can sometimes be difficult to distinguish from cancerous lesions, leading doctors to recommend removal if the diagnosis remains uncertain.
Hepatic cysts are frequently encountered as sacs filled with fluid. Simple liver cysts rarely cause problems and typically do not become cancerous. However, if they grow large enough to cause discomfort or obstruct bile ducts, they may need to be drained or surgically removed.
Hepatic adenoma is a less common benign lesion. It carries a small risk of spontaneous rupture and bleeding. It also has a very small risk of malignant transformation.
Cancerous Types of Liver Lesions
Malignant lesions require treatment to prevent spreading. They are categorized as primary liver cancer, originating in the liver, or metastatic liver cancer, which has spread from cancer elsewhere. Metastatic cancer is the most common malignancy found in the liver, often originating from the colon, lung, or breast.
Metastatic lesions contain cells from the primary tumor site, which dictates the treatment approach. The liver is susceptible to secondary tumor growth because its extensive blood supply filters blood from the gastrointestinal tract. Identifying the original cancer site is necessary for treatment.
Primary liver cancer starts within the liver tissue itself. The most prevalent type is Hepatocellular Carcinoma (HCC), which develops from the main liver cells (hepatocytes). Another form is Cholangiocarcinoma, arising from the cells lining the bile ducts. HCC often presents as a single tumor or multiple small nodules, especially in individuals with cirrhosis.
Determining Malignancy: The Diagnostic Process
Distinguishing between benign and malignant lesions involves a precise diagnostic process, often beginning with imaging tests. Ultrasound is frequently the initial tool used to visualize the liver and detect masses. If a lesion is found, detailed imaging, such as a Computed Tomography (CT) scan or Magnetic Resonance Imaging (MRI), is usually performed.
These advanced scans often utilize an injected contrast agent to highlight organs and blood vessels, helping characterize the lesion. The pattern of how a lesion takes up and releases the contrast agent can often confidently diagnose common benign lesions like hemangiomas or FNH. MRI is particularly valuable for soft tissue differentiation and providing high contrast.
Blood tests assess overall liver function and check for tumor markers, which are substances produced by cancer cells. Alpha-fetoprotein (AFP) is the most common tumor marker associated with primary liver cancer, suggesting the presence of HCC when elevated. Definitive confirmation of cancer often requires a liver biopsy, where a small tissue sample is removed using an imaging-guided needle for microscopic examination. A biopsy is performed when imaging is inconclusive or when a precise tissue diagnosis is required to plan treatment.
Management and Treatment Approaches
Management depends entirely on whether the lesion is confirmed benign or malignant. For the majority of benign lesions, such as small hemangiomas and FNH, treatment is unnecessary, and the strategy is watchful waiting. The lesion is monitored with periodic imaging to ensure it does not grow or change. Surgical removal is recommended only if benign lesions grow very large, cause significant symptoms, or carry a risk of rupture or malignant transformation, such as with some hepatic adenomas.
A confirmed malignant lesion necessitates active treatment, tailored to the cancer type and extent. Treatment often involves localized therapies, such as surgical removal (liver resection) or ablation techniques using heat or cold to destroy the tumor. Chemotherapy or radiation therapy may be used to shrink tumors or kill cancer cells throughout the body. For select patients with early-stage HCC and underlying liver disease, a liver transplant may be considered as a curative option.