Echinococcosis classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor-In-Chief: Mahshid Mir, M.D. [2] Cafer Zorkun, M.D., Ph.D. [3]; Kalsang Dolma, M.B.B.S.[4]

Overview

Echinococcosis is classified based on the site of infection and the type of tapeworm causing the infection, into cystic echinococcosis and alveolar echinococcosis. It can also be classified based on the ultrasound findings and appearance. Based on WHO classification, cystic echinococcus can be classified to 5 stages: CE1, CE2, CE3a, CE3b, CE4, CE5.

Based on the site of infection, echinococcosis can be classified into:^[1]

Based on an international classification, cystic echinococcosis can be classified based on the ultrasound features into 5 categories:^[1]

Type 1 and 2
- Active fertile cysts that contain viable protoscoleces
Type 3
- Transitional stage cysts, as a result of host immune response or therapy
Type 4 and 5
- Inactive and degenerative cysts which have lost their fertility

This classification system can be helpful for application in clinical and field epidemiological setting.

CE: cystic echinococcus.

WHO stage	Description	Stage	Size
CE1	Unilocular unechoic cystic lesion with double line sign	Active	<5 cm
CE1	Unilocular unechoic cystic lesion with double line sign	Active	>5 cm
CE2	Multiseptated, “rosette-like” “honeycomb” cyst	Active	Any
CE3a	Cyst with detached membranes (water-lily sign)	Transitional	<5 cm
CE3a	Cyst with detached membranes (water-lily sign)	Transitional	>5 cm
CE3b	Cyst with daughter cysts in solid matrix	Transitional	Any
CE4	Cyst with heterogenous hypoechoic/hyperechoic contents; no daughter cysts	Inactive	Any
CE5	Solid plus calcified wall	Inactive	Any

↑ ^1.0 ^1.1 Working Group, WHO Informal (2003). “International classification of ultrasound images in cystic echinococcosis for application in clinical and field epidemiological settings”. Acta Tropica. 85 (2): 253–261. doi:10.1016/S0001-706X(02)00223-1. ISSN 0001-706X.
↑ Junghanss T, da Silva AM, Horton J, Chiodini PL, Brunetti E (2008). “Clinical management of cystic echinococcosis: state of the art, problems, and perspectives”. Am. J. Trop. Med. Hyg. 79 (3): 301–11. PMID 18784219.
↑ Brunetti E, Kern P, Vuitton DA (2010). “Expert consensus for the diagnosis and treatment of cystic and alveolar echinococcosis in humans”. Acta Trop. 114 (1): 1–16. doi:10.1016/j.actatropica.2009.11.001. PMID 19931502.