GI Radiology > Liver > Masses > Cysts

Hepatic Masses

Simple Cysts

  1. Pathogenesis:
  • The most common liver masses.
  • May be solitary or multiple.
  • Cysts are found in 2-10% of population, has increased frequency with age, and is more common in females aged 50-70.
  • True hepatic cysts have bile duct origin and cuboidal epithelial lining. They are idiopathic, usually asymptomatic, and variable in size. They cannot be distinguished from cysts that arise from prior hematomas or abscesses.
  • They can be associated with other disease processes, such as tuberous sclerosis and polycystic kidney disease.
  • ~40% of patients with polycystic kidney disease have liver cysts. ~ 60% of patients with multiple liver cysts have polycystic kidney disease.
  1. Radiographic findings of a simple hepatic cyst (arrows):
  • U/S (95-99% accurate): a. Anechoic, b. Posterior acoustic enhancement (increased transmitted sound), c. Well-defined or imperceptible walls.

  • Noncontrast CT: density of less than 20 HU, well-defined margins, no perceptible wall (arrow).
  • Contrast CT: no enhancement after contrast administration.

  • MRI: a. T1-weighted: homogeneously hypointense (arrowhead); b. T2-weighted: homogeneously hyperintense (arrow) due to water property (comparable to the intensity of CSF or gall-bladder bile).  

Note: cysts can be confused with hemangiomas on T2-weighted MRI.  However, on T1-weighted with Gd-DTPA, cysts do not enhance whereas hemangiomas do in a centripetal manner.

A                                                                                   B                                                                    

  1. Differential diagnoses of a cystic liver mass with internal echoes, thick septations, or a perceptible wall noted on U/S include:
    1. Hemorrhagic cyst
    2. Abscess
    3. Echinococcal cyst
    4. Biliary cystadenoma
    5. Cystic metastasis (e.g. ovarian)
    6. HCC with necrosis

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