Liver Pathology Part II

Hepatic Disease Overview

Cystic Lesions

• Cysts can be congenital or acquired, solitary or multiple.

• Differential Diagnosis:

  • Simple cyst

  • Polycystic liver disease

  • Hydatid cyst

  • Cystic tumors

  • Abscess

Simple Hepatic Cysts

• Usually incidental findings; most patients asymptomatic.

• Larger cysts may cause:

  • Pain

  • Mass effects indicating serious conditions (infection, abscess, necrotic lesions)

• More prevalent in females.

• Sonographic Findings:

  • Thin wall

  • Well-defined borders

  • Anechoic with posterior enhancement and edge shadowing.

• Complications:

  • Hemorrhage may cause pain.

  • Calcification can cause shadowing.

  • Example Images:

    • Solitary hepatic cyst with increased through-transmission.

    • Complex liver cyst due to hemorrhage.

Polycystic Liver Disease

• Inherited in an autosomal dominant pattern.

• 50%-74% of patients with polycystic renal disease also have hepatic cysts.

• Cysts are typically small (<2-3 cm) and multiple throughout the liver parenchyma.

• Liver function tests usually normal.

• Sonographic Findings:

  • Anechoic cysts with well-defined borders and acoustic enhancement.

Infectious Diseases of the Liver

• Hepatic abscesses often result from biliary tract disease, surgery, or trauma.

• Types of abscesses:

  • Intrahepatic

  • Subhepatic

  • Subphrenic

Pyogenic Abscess

• Caused by infection (e.g., appendicitis, cholecystitis).

• Common in the right lobe of the liver.

• Clinical Presentation:

  • Fever, nausea, vomiting, RUQ pain, hepatomegaly.

• Laboratory Findings:

  • Elevated LFTs and leukocytosis.

• Common Organisms:

  • Escherichia coli, anaerobes.

• Aspiration confirmation needed.

• Sonographic Findings:

  • Hypoechoic with acoustic enhancement or irregular thick walls.

  • If gas is present, hyperechoic with dirty shadowing.

Amebic Abscess

• Caused by Entamoeba histolytica from intestines.

• Symptoms include right upper quadrant pain, fever, bloody diarrhea, leukocytosis.

• Differentiation Challenge:

  • History of travel indicates a higher probability of amebic abscess.

• Aspiration may be needed.

• Sonographic Features:

  • Typically hypoechoic with low-level echoes, complex mass appearance.

Fungal Abscess (Candidiasis)

• Caused by Candida species, often in immunocompromised hosts.

• Symptoms:

  • RUQ pain, fever, and hepatomegaly.

Echinococcal Cyst (Hydatid Cyst)

• Caused by Echinococcus granulosus from contact with infected dog feces.

• Symptoms include low-grade fever and right upper quadrant tenderness.

• Treatment may involve surgical resection or medication.

• Sonographic Appearance:

  • Variable; can include honeycomb appearance, floating membranes, or cysts within cysts.

Schistosomiasis

• Parasitic infection prevalent in tropical regions.

• Eggs reach the liver via the portal vein, causing periportal fibrosis.

• Sonographic Findings:

  • Occluded intrahepatic portal veins, thickened portal vein walls.

Granulomas

• Present as small calcifications in liver and spleen due to infections like Histoplasmosis or Tuberculosis.

Benign Hepatic Tumors

• Types:

  • Cavernous hemangioma

  • Focal nodular hyperplasia (FNH)

  • Hepatic Lipoma

  • Hepatic adenoma

  • Hepatic Hematoma

Cavernous Hemangioma

• Most common benign liver neoplasm, usually asymptomatic.

• Characterized as a hyperechoic mass with acoustic enhancement.

• Increased size possible with estrogen stimulation (pregnancy).

Focal Nodular Hyperplasia (FNH)

• Second most common benign liver mass.

• Asymptomatic, may have a central scar visualized via imaging.

• Sonographic appearance: solitary, well-circumscribed mass that can be isoechoic, hyperechoic, or hypoechoic.

Hepatic Lipoma

• Rare, asymptomatic fatty tumors.

• Appears hyperechoic with propagation speed artifact.

Hepatic Adenoma

• Rare benign tumors often linked to oral contraceptive use.

• Asymptomatic, typically hyperechoic with central hypoechoic areas due to hemorrhage.

Hepatic Hematoma

• Resulting from trauma/surgery, can be intrahepatic or subcapsular.

• Appearance varies based on age, with initial hemorrhage appearing echogenic.

Malignant Hepatic Neoplasms

• Types:

  • Hepatocellular Carcinoma

  • Metastatic liver disease

Hepatocellular Carcinoma (HCC)

• Most common primary liver malignancy, frequently associated with cirrhosis.

• Symptoms include abnormal LFTs, unexplained weight loss, and hepatomegaly.

• Tumor marker: serum alpha-fetoprotein (AFP).

• Sonographic appearance can range from solitary hypoechoic masses to heterogeneous masses throughout the liver.

Metastatic Liver Disease

• Most common type of liver neoplasia; cells enter through portal veins or lymphatic channels.

• Primary cancers: gastrointestinal, breast, lung cancers.

• Clinical symptoms include weight loss, jaundice, RUQ pain, and ascites.

• Sonographic appearance varies (hyperechoic, hypoechoic, calcified lesions).

Lymphoma

• Includes Hodgkin's and non-Hodgkin's lymphoma.

• Sonographic Findings:

  • Well-defined small hypoechoic nodules, diffuse infiltrative disease, abdominal lymphadenopathy.

Liver Transplantation

• Types:

  • Orthotopic (cadaveric liver replaces recipient liver)

  • Heterotopic (part of donor liver transplanted while recipient liver remains)

• Conducted to eliminate irreversible diseases.

• Indications for adults: cirrhosis; for children: biliary atresia.

• Common complications include hepatomegaly and infections.

• Surgical procedure involves several anastomoses:

  • Extrahepatic portal vein

  • Hepatic artery

  • Suprahepatic and possibly infrahepatic IVC.

• Note: Sonography is not reliable for diagnosing transplant rejection; biopsy is required.