[Pathology of liver tumors]

Neoplasms of the liver may arise from any cell type within the liver parenchyma. Hepatocellular carcinoma is by far the most common primary malignant tumour of the liver in adults. Indeed, it is one of the most common tumours in the world with striking geographic differences. These incidence rates can be explained by differences in Hepatitis-Virus carrier rates which they closely reflect. Nearly 10% of malignant liver tumors are represented by cholangiocarcinoma which originates from small intrahepatic bile ducts. Hepatoblastoma accounts for approximately 5% of malignancies in childhood. Most hepatoblastomas fall into epithelial or mixed epithelial and mesenchymal categories. Fetal-type cells and embryonal-type cells represent the epithelial components. Rare primary malignant non-epithelial tumours are angiosarcomas, leiomyosarcomas or fibrosarcomas, arising from vascular or mesenchymal components of the liver respectively. All types of Hodgkin and Non-Hodgkin Lymphomas may secondarily involve the liver. Most primary hepatic lymphomas are of diffuse large B-cell type and are extremely rare.