Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Review Review Urol Int 2008;81:247–251 DOI: 10.1159/000151398 Keratinizing Squamous Metaplasia of the Bladder: A Review Introduction Keratinizing squamous metaplasia is infrequently found in bladder biopsies and its clinical significance re- mains unclear, with some studies linking it to the devel- opment of invasive squamous cell carcinoma (SCC). In this review we analyzed all the literature on this topic to investigate the link between keratinizing squa- mous metaplasia and the risk of subsequent development of invasive cancer. In particular we tried to find whether there was any consensus over the management and fol- low-up of these patients. Materials and Methods We reviewed the literature on keratinizing squamous meta- plasia, searching using the keywords ‘keratinizing (keratinising) squamous metaplasia’, ‘leukoplakia’ and ‘squamous cell cancer’. A Medline search of the English literature from January 1960 to December 2006 inclusive was done on OVID. All relevant articles were studied in full. Results Incidence and Aetiology Keratinizing squamous metaplasia of the bladder is rare. The incidence has been reported as 1: 10,000 of hos- pital admissions [1]. However analysis of the literature Key Words Keratinizing squamous metaplasia  Squamous cell carcinoma Abstract Aims: Keratinizing squamous metaplasia is infrequently found in bladder biopsies and its clinical significance re- mains unclear, with studies linking it to the development of invasive squamous cell carcinoma. Once diagnosed, there is a dilemma how to treat and follow-up this group. Methods: We reviewed the literature on the topic with particular em- phasis on natural history, management and subsequent fol- low-up. Results: Keratinizing squamous metaplasia of the bladder is rare. Pathognomonic findings on biopsy are re- quired to confirm the diagnosis. Both synchronous diagno- sis of urothelial tumour and subsequent tumour develop- ment on follow-up has been identified. Risk of malignant transformation increases in the presence of dysplasia as well as with extensive keratinization. Lesions should be treated with local transurethral resection. Considering the lack of evidence cystectomy cannot be justified for those with ex- tensive lesions. Conclusion: Currently there is not enough data to identify keratinizing squamous metaplasia of the bladder as a pre-malignant condition; this term being re- served for those with obvious histological dysplasia. How- ever at present all patients should undergo regular follow- up. Copyright © 2008 S. Karger AG, Basel Imran Ahmad Beatson Institute for Cancer Research Garscube Estate, Switchback Road Bearsden, Glasgow G61 1BD (UK) Tel. +44 141 330 3973, Fax +44 141 201 2987, E-Mail imranahmad@doctors.net.uk © 2008 S. Karger AG, Basel 0042–1138/08/0813–0247$24.50/0 Accessible online at: www.karger.com/uin Imran Ahmad a Robert J. Barnetson b Nalagatla Sarath Krishna c a Beatson Institute for Cancer Research and Departments of b Pathology and c Urology, Southern General Hospital, Glasgow, UK