Last updated on May 14, 2019 at 20:41
The liver and lungs share the unfortunate throne of being those organs that are most frequently metastasized into. The most common hepatic neoplasms are neoplastic carcinomas from the colon, lung or breast.
The liver obviously also has primary tumors.
Tumor-like lesions of the liver
Polycystic liver disease is a condition where cysts form in the liver. Polycystic liver disease most frequently occur in association with polycystic kidney disease or on its own (very rare).
Focal nodular hyperplasia (FNH) is a localized, well-demarcated lesion consisting of hyperplastic hepatocytes nodules with a characteristic central stellate scar. It’s not a true neoplasm but instead a response to some abnormal vascular flow. It occurs most commonly in females. Contraceptives increase the risk. These lesions are usually not removed as they pose no risk.
Echinococcus cyst was described in topic 11.
Benign liver tumors
These benign tumors may be mistaken for a carcinoma on imaging.
Hepatocellular (or hepatic) adenoma is a benign tumor that usually occurs in women. It’s also associated with contraceptive use. They can rupture and cause life-threatening haemorrhage and should therefore be removed when found. They have the possibility to turn malignant as well, further indicating surgical removal.
Hepatic haemangioma is associated with contraceptives. It has no malignant potential and is therefore not usually removed.
Bile duct adenoma is a benign condition of the bile ducts that is often found incidentally. It can easily be confused with a malignant tumor and can therefore interfere with differential diagnosis.
Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver. In almost all cases it develops in an already cirrhotic liver, so the risk factors for HCC are the same as those for cirrhosis.
- Chronic HBV or HCV infection*
- Non-alcoholic fatty liver disease*
- Alcoholic liver disease
- Drugs like paracetamol
Those marked with asterisk (*) are at especially high risk for developing HCC after cirrhosis. Hepatitis B may incorporate the HBsAg into the host genome. Hepatitis C has no such capacity. Both viruses increase cancer risk due to the chronic inflammation and high cell turnover they cause.
Aflatoxin is a toxin produced by aspergillus fungi that can contaminate food. It can cause HCC without cirrhosis. Aflatoxin causes a very characteristic mutation in the p53 gene called a signature mutation. If this mutation is present in an HCC it’s certain that the etiology was aflatoxin.
Pathomechanism: It usually develops from a dysplastic nodule in a cirrhotic liver. This nodule is a precancerous lesion that can be visualized on ultrasound.
A special form of HCC called fibrolamellar HCC is very rare. Only 200 new cases are diagnosed every year. This type of HCC develops in non-cirrhotic livers.
Diagnosis of HCC is based on AFP (α-fetoprotein) screening and ultrasound. In patients with cirrhosis or chronic viral hepatitis AFP is regularly screened for HCC. Biopsy is rarely performed due to the risk of spreading the tumor cells during the procedure.
Prognosis: HCC normally doesn’t produce significant symptoms until it’s already at an advanced stage. Any symptoms it would produce would be masked by the underlying cirrhosis. It’s also rarely possible to completely excise the tumor. This gives it a poor prognosis.
Other malignant tumors
Cholangiocellular carcinoma can be intrahepatic in 10% of cases. More about this in topic 16.
Hepatoblastoma is a rare childhood tumor that originates in liver precursor tissue. AFP is elevated and it usually presents as an abdominal mass in children younger than 3 years.
Hepatic angiosarcoma is very rare, accounting for around 1% of all primary liver tumors.
14. Cirrhosis and hepatic failure
16. Cholelithiasis (aetiology and complications) and pathology of the extrahepatic biliary tract