Liver Pathology — Diffuse and Focal Abnormalities

Flashcards cover major diffuse and focal liver pathologies including fatty liver, hepatitis, cirrhosis, tumors, abscesses, cysts, parasitic diseases, trauma, and imaging concepts from the lecture notes.

Fatty infiltration (fatty liver / steatosis)

An acquired, reversible metabolic disorder characterized by accumulation of triglycerides in hepatocytes; caused by major liver injury or systemic/metabolic disorders; risk factors include obesity, excessive alcohol, poor lipid control, diabetes, excess corticosteroids, pregnancy, total parenteral nutrition, severe hepatitis, glycogen storage disease, and cystic fibrosis.

Focal fatty infiltration

Localized regions of fat accumulation within an otherwise fatty liver; not the entire liver is involved.

Focal fatty sparing

Regions of normal liver within fatty infiltration, commonly adjacent to the gallbladder, porta hepatis, caudate lobe, or liver margins.

Hepatitis

Inflammation and infection of the liver; can be viral, bacterial, fungal, or parasitic; mild inflammation impairs hepatocyte function, while severe inflammation/necrosis can obstruct blood and bile flow; may elevate ALT, AST, and bilirubin.

Cirrhosis

Chronic degenerative liver disease with fibrous tissue, parenchymal degeneration, and fat infiltration; lobules are disorganized due to simultaneous necrosis, regeneration, and diffuse fibrosis; two forms: micronodular and macronodular.

Micronodular cirrhosis

Cirrhosis characterized by numerous small nodules, often associated with chronic alcohol abuse.

Macronodular cirrhosis

Cirrhosis characterized by fewer, larger nodules, often due to chronic viral hepatitis or other infection.

Glycogen storage disease type I (von Gierke)

Inherited disorder with excessive glycogen deposition in liver and kidneys; hepatomegaly and metabolic abnormalities.

Hemochromatosis

Iron storage disease with excess iron deposition in the liver; can lead to hepatomegaly and cirrhosis; ultrasound may show increased hepatic echogenicity.

Wilson disease

Copper deposition disease affecting the liver (and other organs); inherited disorder leading to hepatic pathology.

Biliary obstruction (proximal to cystic duct)

Obstruction proximal to the cystic duct; causes include gallstones, carcinoma of the common bile duct, porta hepatis metastasis; signs include jaundice and pruritus; labs show elevated direct bilirubin and alkaline phosphatase.

Biliary obstruction (distal to cystic duct)

Obstruction distal to the cystic duct; causes include stones in the common duct, porta hepatis mass, or common duct stricture; symptoms include RUQ pain, jaundice, pruritus; labs show elevated direct bilirubin and ALP.

Extrahepatic mass (biliary obstruction)

An external mass near the porta hepatis that causes biliary obstruction with signs of jaundice and altered liver function tests.

Passive hepatic congestion

Liver congestion due to congestive heart failure; hepatomegaly; liver function tests are normal or only mildly elevated.

Simple hepatic cyst

Benign focal liver lesion: well-demarcated, thin-walled, anechoic with posterior acoustic enhancement; often asymptomatic.

Polycystic liver disease

Autosomal dominant condition; associated with polycystic kidney disease; multiple small hepatic cysts that may enlarge and cause biliary obstruction; about 50–74% have PKD.

Cavernous hemangioma

Most common benign liver tumor; composed of large, blood-filled vascular spaces; usually asymptomatic; on ultrasound, often heterogeneous due to vascular components.

Liver cell adenoma

Benign tumor more common in women; linked to oral contraceptives; risk of rupture/bleeding; increased in type I glycogen storage disease; surgical resection recommended due to malignant transformation risk.

Focal nodular hyperplasia (FNH)

Second most common benign liver mass; typically in women <40; well-circumscribed, often subcapsular; may have a central fibrous scar; composed of normal hepatocytes, Kupffer cells, bile duct elements, and fibrous tissue.

Hepatocellular carcinoma (HCC)

Most common primary malignant liver tumor; strongly associated with cirrhosis and chronic hepatitis B/C; patterns include solitary mass, multiple nodules, or diffuse infiltration; may invade portal/hepatic veins and cause Budd-Chiari syndrome.

Metastatic liver disease

Most common liver neoplasm; usually from colon, breast, or lung; presents as multiple well-defined iso-, hyper-, or hypoechoic lesions; may show central necrosis.

Hepatoblastoma

Most common malignant liver tumor in infants/children under 2; presents as enlarged abdominal mass; associated with Beckwith-Wiedemann syndrome and familial adenomatous polyposis; elevated AFP; may metastasize and invade portal vein.

Infantile hepatic hemangioma (hepatic hemangioendothelioma)

Benign vascular tumor in neonates; rapid growth; can cause congestive heart failure; often regresses spontaneously by 12–18 months.

Lymphoma involving the liver

Hepatic involvement by Hodgkin or non-Hodgkin lymphoma; hepatomegaly with normal or diffusely abnormal parenchymal echoes; may have focal hypoechoic masses.

Schistosomiasis

Parasitic infection; schistosome worms penetrate skin and migrate to the liver; causes portal hypertension; involves portal veins; differential for portal hypertension or thrombus.

Amebic abscess

Liver abscess caused by Entamoeba histolytica; spread via portal vein from colonic infection; ultrasound shows necrotic material (not pus); caused by amebiasis.

Pyogenic (bacterial) liver abscess

Most common type of hepatic abscess (about 80%); routes of infection include biliary tract disease (most common), portal vein, hepatic artery, direct extension, or trauma.

Echinococcal cyst (hydatid disease)

Hepatic infection by Echinococcus tapeworm; life cycle involves dogs and sheep; cyst may contain daughter cysts; water-lily sign indicates floating membranes within the cyst.

Water-lily sign

Radiologic/sonographic sign of echinococcal cyst showing floating membranes inside the cyst.

Fungal abscess (candidiasis) of the liver

Liver infection by Candida in immunocompromised patients; imaging may show a wheel-within-a-wheel or bull’s-eye appearance; typically a uniformly hypoechoic focus.

Pneumocystis carinii pneumonia (PCP)

Opportunistic infection common in AIDS and immunocompromised patients; can involve the liver with a pattern of diffuse tiny nonshadowing echogenic foci or calcifications.

Chronic granulomatous disease

Congenital defect in phagocytes reducing bacterial killing; predisposes to severe infections; liver lesion may appear as poorly marginated hypoechoic mass with possible calcifications and posterior shadowing.

Elastography

Ultrasound technique that measures tissue stiffness; malignant lesions are typically stiffer; used to assess fibrosis and to identify patients with little to no fibrosis besides cirrhosis.

Liver biopsy with ultrasound guidance

Ultrasound-guided procedure to obtain liver tissue for histology and diagnosis.

Hepatic trauma

Liver is a commonly injured organ after trauma; lacerations range from small to large; right lobe more commonly affected; management depends on laceration size, hemoperitoneum, and clinical status.

Budd-Chiari syndrome

Hepatic venous outflow obstruction; can be associated with tumor invasion (e.g., by HCC); leads to hepatic congestion and portal hypertension.