Liver & intrahepatic bile ducts
Infectious nonviral

Topic Completed: 1 May 2012

Revised: 23 January 2019, last major update May 2012

Copyright: (c) 2002-2017,, Inc.

PubMed Search: Schistosomiasis[TI] liver[TI] full text[sb]

Komal Arora, M.D.
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Cite this page: Arora K. Schistosomiasis. website. Accessed September 20th, 2020.
Definition / general
  • Flat worms (trematodes) with species S. haematobium, S. intercalatum, S. japonicum, S. mansoni, S. mekongi
  • All but S. haematobium parasitize intestinal venules and may spread to liver
  • Infect millions in Asia, Africa and South America; rare in US

Infectious cycle:
  • Fresh water snails release cercarial form into water
  • Cercarie are mobile and penetrate human skin or mucosa, enter circulation, pass through lungs and lodge in hepatic branches of portal vein
  • Mature into adults, copulate and migrate to colonic and rectal submucosa where female releases ova that enter colonic lumen, are defecated and infect other snails
  • Ova may also enter portal circulation and cause periportal fibrosis
  • Rarely adult S. mansoni worms are identified in hepatic branches of portal vein (10 - 16 mm)

  • References: Parasite Immunol 2009;31:656
Gross description
  • Pipe stem fibrosis of cut surface
  • No cirrhosis unless coexisting hepatitis B
Microscopic (histologic) description
  • Portal eosinophilic infiltrate with granulomas containing ova with characteristic lateral spine; dense periportal fibrosis
Microscopic (histologic) images

Images hosted on other servers:

Eggs in intestinal mucosa

Dense periportal fibrosis

Images contributed by Dr. Keloth Pradeep, Wrexham Maelor Hospital (United Kingdom):

82 year old woman with liver biopsy for presumed liver metastases, based on CT / MRI findings: schistosomial ova and metastatic adenocarcinoma in liver

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