• Clinical science

Benign liver tumors and hepatic cysts


Benign liver tumors and hepatic cysts are common and may occur in all age groups. Benign liver tumors are especially frequent in young women and include hepatic hemangiomas, focal nodular hyperplasia (FNH), and hepatocellular adenoma (also known as liver cell adenoma). Use of oral contraceptives, especially such containing estrogen, and pregnancy are associated with an increased risk of hepatocellular adenoma. Hepatic cysts include solitary and hydatid (echinococcal) cysts. Benign liver tumors and cysts are mainly asymptomatic and are often incidental findings in patients undergoing abdominal imaging. However, in some cases (e.g., large lesions), symptoms like upper abdominal pain and postprandial fullness may occur. Diagnosis is usually based on imaging, but may require biopsy in unclear cases. Treatment is generally conservative; surgery is reserved for specific lesion types and the presence of symptoms or complications.

Benign liver tumors


  • Epidemiology
    • Frequency: hepatic hemangioma (most common) > focal nodular hyperplasia (FNH) > hepatocellular adenoma (rare)
    • Sex: > (∼ 6:1)
    • Age: can appear at any age, but mostly affects young women
    • Most often an incidental finding on imaging tests
  • Etiology
  • Symptoms/clinical findings
    • Usually asymptomatic
    • Large tumors → upper abdominal pain, fullness, and nausea
  • Diagnostics
    • Best initial test: ultrasound
    • Further imaging
      • Contrast-enhanced CT
      • MRI
    • Biopsy: to confirm diagnosis if imaging is inconclusive
  • Treatment
    • Conservative treatment is often sufficient
    • Surgical treatment if symptomatic and/or complications arise
    • For hepatic adenoma
      • Discontinue oral contraceptives
      • If the tumor is > 5 cm → surgical resection due to increased risk of rupture, bleeding, or malignant transformation
  • Complications
    • Rupture and bleeding

The typical clinical picture of a hepatic adenoma is a young woman with a history of oral contraceptive or anabolic steroid use and upper right abdominal pain.

Additional diagnostic features

Hepatic hemangioma Focal nodular hyperplasia (FNH) Hepatocellular adenoma


  • Usually well-demarcated, homogeneous, hyperechoic (pale)
  • Homogeneous, hypoechoic to isoechoic
  • Round/oval, sharply defined
  • Central, stellate scar
  • No characteristic vascularization
  • Mainly isoechoic
  • Inhomogenous due to bleeding
  • More frequent in the right lobe of the liver
Histology (Biopsy)
  • Cavernous vascular spaces of variable size, lined by flat endothelial cells
  • Localized hepatocyte nodules, with large malformed arterial branches and centralized fibrous tissue (central stellate scar)
  • Enlarged hepatocytes, with small and regular nuclei, cytoplasmic glycogen and lipid deposits
  • Arranged in sheets or 2-cell thick cords
  • Normal hepatic lobular architecture is absent
Contrast-enhanced CT
  • Well-demarcated
  • Early arterial phase discontinuous, nodular, or peripheral enhancement
  • Subsequent gradual centripetal enhancement (iris diaphragm phenomenon)
  • Delayed-phase hyperintensity due to retention of contrast
  • Early arterial phase enhancement
  • Rapid washout of the contrast medium in the portal venous phase
  • Central scar (“nest of vessels”)
  • Well-demarcated
  • Heterogenous density due to the presence of fat, glycogen, and hemorrhagic products
  • Early arterial phase peripheral enhancement due to feeding arteries
  • Subsequent centripetal pattern of enhancement
  • No retention of contrast due to arteriovenous shunting on delayed-phase
Gross pathology
  • Macroscopic: possibly pedunculated, cystic lesions with a dark color
  • Macroscopic: light yellow color compared with the surrounding liver tissue
  • Microscopic: fibrous scars


Hepatic cysts


Differential diagnoses