Schistosomiasis-related cystitis

Author: Turki Al-Hussain, M.D.(see Authors page)

Revised: 7 June 2016, last major update March 2015

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Schistosomiasis [title] bladder
Cite this page: Schistosomiasis-related cystitis. website. Accessed December 11th, 2018.
Definition / general
  • Deposition of Schistosoma eggs in bladder causes eosinophilic inflammation, necrosis and ulceration, followed by fibrosis with chronic inflammatory infiltrate
  • Schistosoma haematobium infection is common in Africa and the Middle East, and is the world's leading cause of hematuria
  • Uncommon in US, except in immigrants
  • Schistosoma larvae (cercariae) are released from snails into water and penetrate human skin exposed to infected water
  • Larvae travel to the lungs and liver of the human host, where they reside until they mature
  • After maturation, adult worm pairs travel to pelvic veins, where oviposition (egg laying) occurs
  • Eggs are deposited in bladder wall vessels and incite a granulomatous response that results in polypoid lesions
  • Eggs also incite chronic inflammatory response and fibrosis, a predisposing factor for squamous cell carcinoma
  • Eggs are excreted in urine
  • Adult worms may live for many years, and even after their death, large numbers of calcified eggs can be found in bladder wall
Diagrams / tables

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Life cycle

Clinical features
  • May clinically simulate urothelial carcinoma
  • Symptoms are nonspecific; common symptoms are dysuria, suprapubic pain, microscopic hematuria and frequency
  • Complications include hydroureter, hydronephrosis, bladder ulcer, polyposis, bacterial urinary tract infection, renal failure, bladder cancer (squamous cell carcinoma, adenocarcinoma and rarely urothelial carcinoma, Hum Pathol 1986;17:333)
  • Complications may occur during inactive phase of disease, when diagnosis is most difficult
Case reports
  • S. haematobium eggs are 110-170 x 40-70 microns, oval with terminal spine
Clinical images

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Schistosoma haematobium fluke

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Adult (female and male)

Gross images

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Related invasive squamous cell carcinoma

Microscopic (histologic) description
  • Early changes are necrosis and eosinophils with mucosal ulceration
  • Late changes are fibrosis with lymphocytes, histiocytes, foreign body granulomas and dystrophic calcification
  • Schistosoma eggs are present, which may calcified over time
Microscopic (histologic) images

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Schistosoma haematobium eggs are oval with a terminal spine

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Eggs in the muscularis propria

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Papillary fronds with inflammatory infiltrate

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Contributed by: Drs. Kiran Alam, Anshu Jain, Veena Maheshwari, Farhan A. Siddiqui and Ershadul Haq, J.N. Medical College (India)

Differential diagnosis