Liver cysts are fluid-filled sacs that develop within the liver. The presence of these cysts often raises concerns about cancer, though the majority are benign. This article explores different types of liver cysts, factors indicating cancer concern, and pathways for diagnosis and management.
Understanding Liver Cysts
Liver cysts are common, often discovered incidentally during imaging for other health concerns. They affect 5% to 18% of people in the U.S. and 5% to 10% worldwide. These cysts are typically asymptomatic, and their size varies significantly. Most liver cysts do not impair normal liver function.
The cause of most simple liver cysts is not fully understood, though they may stem from a malformation present at birth. They are fluid-filled sacs lined with epithelial cells, similar to those in bile ducts. While generally harmless, a small percentage may be malignant or infected, requiring careful assessment.
Common Types of Liver Cysts
Simple liver cysts are the most prevalent type, characterized by thin walls and a fluid-filled interior. They rarely cause symptoms unless large, and have no malignant potential. Polycystic liver disease (PLD) is a rare genetic condition with numerous benign cysts throughout the liver. While large PLD cysts can cause discomfort, they typically do not lead to liver failure.
Hydatid cysts result from a parasitic infection (Echinococcus granulosus tapeworm). These serious, non-cancerous cysts can cause symptoms like abdominal pain, nausea, or jaundice. They are more common in certain geographical areas and identified by daughter cysts or calcifications on imaging.
Rare but potentially malignant cystic lesions include biliary cystadenomas, uncommon benign tumors originating in bile ducts with malignant potential. Their cancerous counterpart is biliary cystadenocarcinoma. These often present as solitary, multilocular cysts, requiring differentiation from benign types.
Cystic metastases are cancerous lesions spread from other body parts, appearing as cysts due to necrosis or mucinous components. They often feature irregular walls, thick septations, or mural nodules. Cystic hepatocellular carcinoma is a rare primary liver cancer that can also present with cystic features.
When a Liver Cyst Raises Cancer Concerns
Imaging characteristics can raise suspicion for malignancy. Worrisome features include internal septations, solid components, thickened or irregular walls, mural nodules, rapid growth, or very large size. Advanced imaging like CT and MRI characterize these features, with MRI useful for identifying hemorrhagic or proteinaceous contents and wall enhancement.
While most cysts are asymptomatic, certain symptoms combined with suspicious imaging warrant closer investigation. These include unexplained weight loss, jaundice, or persistent abdominal pain. Fever may suggest an infected cyst, but not cancer.
Blood tests can offer clues. Tumor markers like CA 19-9 and CEA may be elevated in cancerous or pre-cancerous lesions, though not definitive. A known primary malignancy elsewhere also increases suspicion for cystic metastases.
Biopsy, involving a tissue sample, is not always performed due to risks like spreading cancer cells or rupturing cysts. However, it may be considered in highly suspicious cases to confirm diagnosis.
Diagnosis and Management Pathways
Initial detection and characterization of liver cysts typically involve imaging like ultrasound, CT, and MRI. Ultrasound is often first-line for simple cysts and PLD, visualizing content and wall thickness. For complex or atypical cysts, CT and MRI provide detailed differentiation.
Most simple, asymptomatic liver cysts require no treatment. They are often monitored with periodic imaging to ensure stability. If stable after a few years, further surveillance may not be needed unless new symptoms develop.
Intervention for benign cysts is considered if they cause symptoms, become infected, or rupture. Treatment options include percutaneous aspiration (fluid drainage) or surgical removal (cyst fenestration). Aspiration provides temporary relief, but fluid may reaccumulate.
When a cyst is confirmed cancerous or highly malignant, management shifts. Surgical resection, removing the affected liver part, is often preferred for types like biliary cystadenoma/cystadenocarcinoma and some cystic metastases. Depending on cancer type and stage, chemotherapy or radiation therapy may also be part of the plan. Early detection significantly improves outcomes in malignant cases.