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 those 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.

General

• Epidemiology ^[1]
  • Frequency: hepatic hemangioma (most common) > focal nodular hyperplasia (FNH) > hepatocellular adenoma (rare)
  • Sex: usually ♀ > ♂
    • Hepatic hemangioma: 5:1 female:male ratio ^[2]
    • FNH: 8:1 female:male ratio ^[3]
    • Hepatocellular adenoma: 9:1 female:male ratio ^[4]
  • Age
    • Hepatic hemangioma: peak incidence at age 30–50 ^[2]
    • FNH: can occur at any age but mostly affects young women in the third or fourth decade of life; However, FNH in men is diagnosed later in life. ^[5][6]
    • Hepatocellular adenoma: childbearing age (mostly at age 15–45) ^[4][7]
  • Most often an incidental finding on imaging tests
• Etiology
  • Hepatic hemangioma: possible hormonal component; estrogen therapy associated with increased growth
  • FNH
    • Mostly unknown
    • Suggested to be the result of a localized hyperplastic reaction by hepatocytes to an underlying arteriovenous malformations ^[3]
  • Hepatocellular adenoma: oral contraceptives and anabolic steroids ^[8]
• Clinical features
  • Usually asymptomatic (incidental finding in most cases)
  • Large tumors (especially hepatocellular adenoma) may present with upper abdominal pain, fullness, and nausea.
• Diagnostics
  • Ultrasonography: best initial test
  • Further imaging
    • Contrast-enhanced CT scan: helpful to characterize the lesions and may bring specific signs of large hemangiomas or FNH
    • MRI
  • Biopsy
    • Performed to confirm the diagnosis if imaging is inconclusive
    • Contraindicated in hepatic hemangiomas, as it may cause bleeding
• Treatment ^[9]
  • Conservative treatment is often sufficient for hepatic hemangioma and focal nodular hyperplasia.
  • Surgical treatment if symptomatic and/or complications arise
  • Hepatocellular adenoma
    • Discontinue oral contraceptives
    • Women with symptoms or tumor > 5 cm: indication for surgical resection because of increased risk of rupture, bleeding, or malignant transformation
    • Men with hepatocellular adenoma: indication for surgical resection irrespective of the size of the lesion because of an increased risk of malignant transformation ^[10]
• Follow-up
  • Hepatic hemangioma: regular follow-up ^[2]
  • FNH: ultrasonography every six months for the first three years after diagnosis ^[3]
  • hepatocellular adenoma: CT or MRI at 6- to 12-month intervals ^[10]
• Complications
  • Hepatocellular adenoma ^[8]
    • Risk of malignant transformation
    • Rupture and bleeding: presents with sudden onset of abdominal pain and may cause hemorrhagic shock

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

Additional diagnostic findings ^[11]

Simple hepatic cysts ^[17]

• Etiology: congenital
• Epidemiology
  • Peak incidence: > 50 years
  • Sex: slightly higher in females (1.5:1 female:male ratio) ^[18]
• Clinical features
  • Usually asymptomatic
  • Patients with large cysts may present with dull abdominal pain located in the right upper quadrant, bloating, and early satiety.
• Diagnostics
  • Ultrasonography: anechoic, round lesion with dorsal acoustic enhancement
  • CT: well-delimited lesion; shows no contrast enhancement
• Treatment: laparoscopic resection if symptomatic

Congenital polycystic liver

See polycystic kidney disease.

Hydatid (echinococcal) cysts

See echinococcosis.

• Malignant liver tumors
  • Hepatocellular carcinoma (HCC)
  • Intrahepatic cholangiocellular carcinoma (CCC)
  • Liver metastases
• Liver abscess
• Localized nonspace occupying lesions of the liver
  • Steatohepatitis (fatty liver) with localized steatosis close to the gallbladder and portal vein
  • Regenerative nodules in liver cirrhosis
  • Portal vein thrombosis
  • Accessory lobes of the liver: caudate and quadrate lobes
  • Round ligament of the liver
  • Hepatic inflammatory pseudotumor: a rare hepatic lesion that is associated with other inflammatory lesions (e.g., sclerosing cholangitis, retroperitoneal fibrosis, and autoimmune diseases); most commonly seen in young men ^[19]
• Biloma ^[20]
  • Definition: collection of bile in the form of a cyst (biliary cyst)
  • Etiology
    • Common complication of hemihepatectomy or liver transplantation ^[21][22]
    • Trauma
    • Spontaneous
  • Pathology: insufficient closure of the bile ducts
  • Clinical features
    • Nonspecific
    • Fever, and signs of inflammation
    • Potential jaundice
    • Abdominal pain
  • Diagnostics ^[23][24]
    • Ultrasonography: hypoechoic to anechoic
    • CT: hypodense, possible peripheral contrast enhancement
    • Lab findings: elevated transaminases and bilirubin, and leukocytosis
  • Treatment
    • Drainage and antibiotic treatment in patients with inflammation
    • Spontaneous healing is possible.
    • Surgical repair may be necessary