Liver Tumors Overview

Liver Tumors: Overview

• Liver tumors encompass various types, including benign and malignant.
• Benign tumors include Von Meyenburg complex, hepatocellular adenoma, and focal nodular hyperplasia.
• Malignant tumors include hepatocellular carcinoma and cholangiocarcinoma.

Von Meyenburg Complex

• Also known as bile duct hamartoma or microhamartoma.
• Benign.
• Incidental finding—not clinically significant.
• Resembles liver metastases, concerning for surgeons.
• Formed from incomplete involution of embryonic bile duct remnants.
• Grossly displays single or multiple well-circumscribed nodules.
• Typically gray-white, occasionally green, and less than 5 mm in size.
• Microscopically consists of periportal small clusters of dilated bile ducts within fibrous stroma.
• Epithelial cells are bland, with little inflammation or atypia.

Hepatocellular Adenoma

• Benign neoplasm of hepatocellular origin.
• Usually solitary but may be adenomatous, with more than 10 lesions
• Strong association with oral contraceptive exposure.
• May be asymptomatic or present with abdominal pain or hemorrhage (risk increases with size).
• Grossly, they are solitary, well-circumscribed, and often lighter in color than surrounding liver tissue.
• Microscopically, shows well-defined border with background liver and hepatocytes without atypia.
• Composed of thin-to-moderately thickened cell plates, no interlobular bile ducts and absent portal tracts except at the periphery of the lesion.
• Foci of hemorrhage, ischemia and necrosis.
• No atypia, portal or parenchymal invasion.

Focal Nodular Hyperplasia (FNH)

• Benign non-neoplastic hepatic lesion in a noncirrhotic liver.
• More common in females.
• Pathogenesis not fully understood, potentially a hyperplastic response to a vascular anomaly.
• Radiologically shows a well-demarcated solitary hepatic lesion with a central scar, visible on CT and MRI.
• Grossly appears as a solitary, well-demarcated, unencapsulated, subcapsular hepatic nodule with a central scar on gross examination.
• Microscopically shows bland hepatocytes surrounded by fibrous septa which contain artery branches and varying degrees of bile ductular reaction; variable inflammatory infiltrate; portal tracts absent except at lesion periphery.
• Hepatocytes resemble surrounding liver.

Hepatocellular Carcinoma (HCC)

• Malignant tumor of hepatocellular origin.
• Highest rates in specific geographical areas (Korea, Taiwan, Southeast Asia).
• Risk factors include viral hepatitis B and C, aflatoxins, cirrhosis, hemochromatosis, and alcohol abuse.
• Pathophysiology includes mytotoxins (aflatoxins), cirrhosis, and hepatitis B and C infection.
• The malignant tumor is characterized, in general, by malignant growth with hepatocellular differentiation.
• Grossly appears as a usually large, nonencapsulated, well demarcated, firm, white-tan to gray and nodular mass; likely contains satellite nodules (present in 30% of cases).
• Common to be calcified.
• Classifications: -Mass-forming: solid mass. -Periductal infiltrating: infiltrates along portal tracts. -Intraductal growth: growth within a dilated bile duct.
• Microscopically, presents with patterns like trabecular (most common), clear cell, giant cell, pseudoglandular and sarcomatoid, solid (compact).
• Presence of sinusoidal vessels is a key diagnostic feature; Scanty stroma and polygonal cells with distinct cell membranes and granular eosinophilic cytoplasm; higher N/C ratio than normal, round nuclei with coarse chromatin and thickened nuclear membrane.
• Often contains portal vein thrombosis, vascular invasion, mitotic figures.

Cholangiocarcinoma

• Malignant intrahepatic bile duct tumor.
• Originates from the intrahepatic biliary tree.
• Essential features include unencapsulated, white-tan and firm intrahepatic mass.
• Risk factors include, parasitic infections (liver flukes), choledochal cysts, congenital hepatic fibrosis, other liver diseases, viral hepatitis, chemical exposure (dioxins, thorotrast), obesity, and diabetes, and primary sclerosing cholangitis.
• Grossly: large, nonencapsulated, well-demarcated, firm mass (desmoplastic reaction); white-tan-gray and nodular; frequently found in right liver lobe, satellite nodules present in 30% of cases.
• Can be categorized into mass-forming, periductal infiltrating, or intraductal growth.
• Microscopically shows infiltrating well-formed or cribriform glands in abundant fibrous stroma. Malignant glands typically lined by cells with variable atypia and pleomorphism.

Explore the different types of liver tumors, including benign and malignant forms. This quiz covers various conditions such as Von Meyenburg complex, hepatocellular adenoma, and more. Learn about the features, significance, and classifications of these tumors.