Table of Contents
Definition / general | Gross description | Microscopic (histologic) description | Microscopic (histologic) imagesCite this page: Arora K. Schistosomiasis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/liverschisto.html. Accessed April 23rd, 2024.
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