Keratinizing squamous metaplasia of the bladder: Our experience and current approaches

Abstract

Introduction: Bladder mucosa is anatomically covered by urothelial epithelium. The replacement of the urothelium with stratified squamous cells is defined as squamous metaplasia which can be keratinizing or non-keratinizing. Clinically, it is also known as leukoplakia or keratinizing cystitis of the bladder. Although several etiologic factors have been proposed such as chronic inflammation, irritative stimuli and infection, its pathogenesis is not clearly understood. The natural history of squamous metaplasia and clinical treatment are controversial. Many authors consider squamous metaplasia as a premalignant lesion, so it is fundamental to find an effective treatment to reduce the risk of developing bladder squamous carcinoma. Case description: We report our management of a 58-year-old man with histological evidence of keratinizing squamous metaplasia and severe lower urinary tract symptoms. After repeated transurethral resections, the patient was treated with intravesical instillation of hyaluronic acid showing the regression of the lesion with an improvement of macroscopic appearance followed by the resolution of clinical symptoms. Conclusion: The therapeutic management of keratinizing squamous metaplasia is controversial, and currently no effective medical therapy is available for its treatment. Actually, patients undergo transurethral resections and a multidisciplinary approach is required to avoid cystectomy. Annual cystoscopy with multiple biopsies should be performed to determine the presence of dysplasia. Moreover, the therapeutic treatment with hyaluronic acid instillations could be the starting point and the gold standard in the follow-up of our patient. However, at present, further studies are required to formulate an adequate policy for therapeutic management of this unusual lesion of the bladder mucosa.

Transurethral resection in women with symptomatic keratinizing squamous metaplasia of urinary bladder: A retrospective study of 92 cases

“…Although the fundamental aim of conservative TUR is to eradicate the risk of bladder squamous cancer development, the role of relieving urinary symptoms has also been observed. Benelli et al not only noted the regression of whitish plaque but also found resolution of severe LUTS by repeated TUR . A retrospective study further demonstrated the efficacy of laser surgery in relieving urinary symptoms by destroying bladder metaplasia lesion, with 68% of the 28 patients achieving at least 75% improvement in urinary symptoms at a mean follow‐up duration of 49 months .…”

“…New treatments are being explored. Benelli et al successfully treated a KSM patient with severe LUTS by repeated TUR combined with intravesical instillation of hyaluronic acid . Guo et al found increased epidermal growth factor receptor (EGFR) expression in bladder KSM lesions, suggesting that EGFR may be a candidate treatment target …”

Diffuse Leukoplakia of the Bladder Ostium-Sparing in Patient Treated with Leuprorelin for Breast Cancer

“…Considering the very low complication rate, our study supports transurethral resection as an alternative treatment for patients who are resistant to medical therapy [ 6 ]. Recently, Benelli et al [ 7 ] manage a man affected by LV with hyaluronic acid instillations with resolution of clinical symptoms. It could be considered the starting point and the gold standard in the follow-up of our patient.…”

“…It could be considered the starting point and the gold standard in the follow-up of our patient. However, at present, further studies are required to formulate an adequate policy for therapeutic management of this unusual lesion of the bladder mucosa [ 7 ].…”

Bladder mulberry-like fibroepithelial polyp with calcification and squamous cell metaplasia mimicking bladder carcinoma: case report and literature review

“…14 Furthermore, squamous metaplasia is generally considered as preneoplastic and can develop into squamous carcinoma. 13,14 If bladder FEPs are accompanied by cancer, most researchers recommend further radical cystectomy. 15,16…”