liver lesions - hepatic abscesses, cysts and nodules

see also:

• liver diseases

• these lesions are often found unexpectedly on ultrasound scans or CT scans

• pyogenic hepatic abscesses
  • more frequently located in the right than both or left liver lobes (60-70% vs. 25% and 15% cases, respectively)
  • onset may be occult, especially in the elderly or may present as a PUO
  • may cause R shoulder tip pain if subcapsular and irritate the diaphragm
  • usually have markedly raised inflammatory markers such as CRP (or low albumin) with abnormal LFTs
  • over 90% can be detected on CT or US scan
  • usually require drainage and at least 2-6 weeks of appropriate antibiotic Rx
  • mortality in developed countries is estimated at 2-19% - highest in those who are immunocompromised (including elderly, diabetics, those with cancer), have septic shock or inadequate drainage (those > 5cm, ruptured, have presence of peritonitis or have had inadequate percutaneous drainage should be considered for surgical drainage)
  • aetiology
    • 30-50% arise from biliary tract disease such as cholangitis or choledocholithiasis
    • iatrogenic from liver or biliary procedures
    • liver trauma
    • portal vein bacteraemia
      • appendicitis, diverticulitis, Crohn's disease, colitis, colorectal neoplasms
    • seeding from systemic sepsis via hepatic artery
      • dental procedures, endocarditis, other causes of sepsis
    • direct extension of local sepsis
      • gall bladder empyema, perforated peptic ulcer, subphrenic abscess, renal abscess
    • secondary infection from
      • liver cyst, biliary cyst, malignancy in the liver
    • cryptogenic
  • Gram negative bacilli
    • usually E. coli, Klebsiella pneumoniae, and/or Enterococcus faecalis
    • Klebsiella pneumoniae
      • normally prefers to colonize the small intestine (esp. in those with decreased gastric acid secretion it seems) with later colonization of the large bowel however antibiotic Rx can disturb this colonization and result in dissemination to other tissues, while the capsule polysaccharide is necessary for the colonization of the large intestine ¹⁾
      • is often associated with colitis or colorectal cancers
      • may further seed to the eye, brain or cause nectrotizing fasciitis
  • Gram positive bacteria
    • usually Staph. aureus or Strept. haemolyticus
  • melioidosis
    • caused by Burkholderia pseudomallei, is endemic in Thailand, Cambodia and Northern Australia
• amoebiasis - amoebic abscess
  • mainly in R lobe from ingesting contaminated water or vegetables 8-12 weeks earlier, usually from overseas travel
• echinococcosis (hydatids) - hydatid cysts
  • mainly in sheep farmers
• Fasciola (liver flukes)
  • liver flukes; usually also have eosinophilia; mature flukes are reasonably visible on endoscopic ultrasound;
  • may have heterogeneous patchy hypo-enhancing foci within the liver
  • abscess formation and impacted fluke in intrahepatic bile ducts are less common features
• benign liver cysts
  • usually have thin walls
  • on CT, a hepatic cyst is usually well-circumscribed and has homogeneous hypoattenuation (water attenuation) of around 0-10 HU
  • simple cysts:
    • may be congenital or develop later in life
  • polycystic liver disease (PLD) is a hereditary genetic condition where multiple cysts develop in the liver as they get older. PLD cysts may cause pain, but they usually do not affect liver function.
  • autosomal dominant polycystic kidney disease (ADPKD)
    • hepatic cysts may be seen in ~40% of those with ADPKD
  • von Hippel Lindau disease
    • a highly phenotypically variable and rare genetic disorder
    • tumours &/or cysts may occur in the brain, spine, eyes, kidneys, pancreas, adrenal glands, inner ears, reproductive tract, liver and lung
    • mainly presents in young adults with nearly all having symptoms by age 65yrs
• liquified hepatic haematoma
• “biloma”
  • rare, intrahepatic bile collections or other bilious collections which are discretely organised
  • usually asymptomatic, but may present with symptomatic bile peritonitis
• choledochal cyst
  • rare congenital cystic dilatations of the biliary tree affecting 1 in 100,000 people esp. in east Asia and F:M ratio is 4:1; most are diagnosed by age 10yrs due to pain or jaundice
  • a subset is called Caroli disease
• cystic forms of tumours
  • biliary cystadenoma
  • biliary cystadenocarcinoma
  • cystic hepatic metastases
  • cystic cavernous haemangioma
  • hepatic lymphangioma
  • necrotic neoplasm
  • embryonal sarcoma

• benign tumours
  • haemangioma
    • affect 5% of people esp. women
  • focal nodular hyperplasia
    • mainly in women between the ages of 20 and 30
  • hepatocellular adenoma
    • most often in women of childbearing age.
    • used to be linked to older high dose oral contraceptives
    • large tumours are often excised due to risk of rupture and bleed into the abdominal cavity
  • biliary cystadenoma
    • mainly in middle-aged patients, esp. in women
  • hepatic lymphangioma
    • rare; focally dilated lymphatic channels in the liver
  • multiple biliary hamartomas
    • a rare cause of multiple benign hepatic lesions although are present in 3% of autopsies, they are generally < 5mm in size and not well seen on CT unless they are > 5mm; F:M is 3:1;
• primary hepatic malignant tumours
  • hepatocellular carcinoma
  • biliary cystadenocarcinoma
• secondary hepatic malignant tumours
  • many malignancies spread to the liver
• hepatic tuberculosis (TB)
  • may be either:
    • micronodular -miliary TB
    • macronodular - single or multiple tumour-like masses with target sign