2001 WHO classification of hepatic hydatid cysts

The 2001 World Health Organization (WHO) classification of hepatic hydatid cysts is used to assess the stage of hepatic hydatid cyst on ultrasound and is useful in deciding the appropriate management for it depending on the stage of the cyst. This classification was proposed by the WHO in 2001 and at the time of writing (July 2016) remains the most widely used classification for hepatic hydatid cysts.

  • CL
    • unilocular anechoic cystic lesion without any internal echoes or septations
  • CE 1
    • uniformly anechoic cyst with fine echoes settled in it representing hydatid sand
  • CE 2
    • cyst with multiple septations giving it a multivesicular, rosette or honeycomb appearance within a unilocular mother cyst
    • this stage is the active stage of the cyst
  • CE 3
    • unilocular cyst with daughter cysts having detached laminated membranes appearing as water lily sign
    • this is the transitional stage of the cyst
  • CE 4
    • mixed hypoechoic and hyperechoic contents with absent daughter cysts; these contents give an appearance of a ball of wool (ball of wool sign), indicating the degenerative nature of the cyst
  • CE 5
    • arch-like, thick partially or completely calcified wall
    • this stage of cyst is inactive and infertile


CL: cystic lesion

CE: cystic echinococcosis

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Article information

rID: 26148
Tag: refs
Synonyms or Alternate Spellings:
  • WHO classification of hepatic hydatid cysts
  • World Health Organization 2001 classification of hydatid liver cysts
  • 2001 World Health Organization classification of hepatic hydatid cysts

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