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Histological changes associated with long-term urethral stents
D M Bailey1, S J Foley, J P McFarlane
1Department of Histopathology, King's College School of Medicine and Dentistry, London, UK.
British Journal of Urology
|June 20, 1998
Summary
Long-term urethral stents cause polypoid hyperplasia and inflammation, leading to stent obstruction in many patients. Further study is needed to rule out cancer risk with keratinizing squamous metaplasia.
Area of Science:
- Urology
- Pathology
- Biomaterials Science
Background:
- Urinary tract stents are used to manage various conditions including benign prostatic hyperplasia, recurrent strictures, and detrusor-sphincter dyssynergia.
- Long-term indwelling stents can lead to significant tissue reactions and complications.
Purpose of the Study:
- To histologically evaluate tissue changes in patients with long-term external sphincter, prostatic, and urethral stents.
- To understand the incorporation process of stents into the urethral wall and associated pathologies.
Main Methods:
- Histological examination of urethral mucosa overlying indwelling stents in 18 patients (mean indwelling time 3.5 years).
- Biopsies were taken from mucosa over patent stents and from two stents with occluded lumens.
- Patients had stents for detrusor-sphincter dyssynergia, benign prostatic hyperplasia, or recurrent urethral strictures.
Main Results:
- Polypoid hyperplasia of the mucosa was observed in 11 of 18 patients, integrating with the stent mesh.
- Chronic inflammation, often with plasma cell infiltrates, was prevalent (15 patients).
- Squamous metaplasia (non-keratinizing and hyperkeratotic), foreign-body granulomas, and microabscesses were also noted.
Conclusions:
- Urinary stents become incorporated into the urethral wall via polypoid hyperplasia, leading to focal stent covering and inflammatory responses.
- Urothelial and connective tissue proliferation can obstruct stent lumens, as seen in 9 patients.
- While no malignancy was found, long-term surveillance is recommended for patients with keratinizing squamous metaplasia due to potential cancer risk.