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Schistosomiasis-related cystitis

Reviewers: Turki Al-Hussain, M.D., Johns Hopkins Medical Centers (see Reviewers page)
Revised: 13 June 2011, last major update March 2011
Copyright: (c) 2003-2011, PathologyOutlines.com, Inc.


● 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


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

● 48 year old woman with bladder mass due to S. mansoni (Rev Soc Bras Med Trop 2009;42:581)


S. haematobium eggs are 110-170 x 40-70 microns, oval with terminal spine


● Antihelminths (eMedicine)

Clinical images

Stalk between bladder and mass

Schistosoma haematobium Fluke

Gross images

Bladder mass

Radical cystoprostatectomy for invasive squamous cell carcinoma in patient with schistosomiasis

Micro 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

Micro images

Schistosoma haematobium eggs are oval with a terminal spine

Eggs in muscularis mucosa with granulomatous response

Egg surrounded by chronic inflammatory cells

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

Transitional epithelium of ureter with schistosome eggs in submucosa and muscle

Schistosome eggs in submucosa

Schistosome eggs in muscle layer

Differential diagnosis

Cystitis (encrusted): irregular calcified aggregates, usually in areas of necrosis
Selective Internal Radiation Therapy (SIRT): microspheres may look similar, but are more spherical than schistosoma eggs (Amin: Diagnostic Pathology: Genitourinary; 2010 (1st ed))

End of Bladder > Cystitis > Schistosomiasis-related cystitis

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