1 3 Int Urol Nephrol DOI 10.1007/s11255-015-0966-4 UROLOGY – LETTER TO THE EDITOR Keratinising cystitis with intestinal metaplasia following a Crohn’s vesico-intestinal fistula Deepak Batura 1 · Grigorios Mitsopoulos 2 Received: 25 March 2015 / Accepted: 27 March 2015 © Springer Science+Business Media Dordrecht 2015 melanocytic population. There was no evidence of dyspla- sia or malignancy. She is currently being followed-up by six-monthly cystoscopic biopsies. Keratinising cystitis is a sub-type of squamous meta- plasia. It is more common in males and is usually asso- ciated with chronic irritation. It usually presents with haematuria, dysuria and urgency. Most keratinised areas are whitish deposits, though pigmented areas have been described [1]. This patient presented with black mem- brane-like deposits. Endoscopy is not diagnostic, and microscope examination is needed to exclude non-kerati- nizing squamous metaplasia, fungal cystitis, malakoplakia or amyloidosis [2]. Unlike the non-keratinising variety, it is a premalignant condition associated with squamous cell cancer [3]. Extensive keratinization may also result in bladder contracture [4]. Chronic irritation due to UTI and entero-vesical fistula, such as our patient had, predisposes to its development [4, 5]. There is no effective treatment for this enigmatic and challenging condition that can cause significant morbid- ity. Strategies such as antibiotics and vitamin A have not been uniformly helpful. Nor have intravesical instillations of silver nitrate or acetic acid [4]. Transurethral resection of affected areas has been described [2]. This patient did not respond to antibiotics. The keratinising membrane was too extensive and thin to be resected, and therefore, endoscopic surveillance was decided upon. This case highlights the importance of repeat cystos- copy in recurrent UTI, lest evolving underlying conditions be missed. Surveillance assumes greater importance in this patient because of the coexistence of intestinal meta- plasia, as both these types of metaplasia are premalignant, in a rare combination of pathologies. Surveillance is also required for early detection of complications like bladder contracture. Editor, A 45-year-old woman developed an entero-vesical fistula secondary to Crohn’s disease in 2006. She was treated with a right hemicolectomy, anterior resection and bladder repair with omental interposition. An anastomotic leak led to pelvic and presacral sepsis, which was treated by per- cutaneous drainage without defunctioning; however, pre- sacral sepsis persists till date. She is on systemic azathio- prine. She continued to have recurrent UTI after surgery. A cystoscopy in 2009 was normal. UTI recurred despite several courses of appropriate antimicrobials leading to another cystoscopy in 2013 which showed a patchy black membrane over the entire bladder (Fig. 1a, b). The mem- brane peeled away readily with biopsy forceps with under- lying raw areas. Histology of the membrane and mucosa showed keratinising squamous epithelium with prominent keratohyaline granules and foci of glandular epithelium with intestinal metaplasia (Fig. 1c, d). Detached fragments of keratinous debris were seen along with bacteria. Tissue culture of the membrane isolated Enterococcus faecalis and Morganella morganii. PAS and Grocott’s stains for fungi were negative. Because of the colour of the membrane, melanin deposits were sought. Masson-Fontana stain did not detect melanin deposits within epithelial cells. S100, HMB 45 and Melan A immunostains failed to identify any * Deepak Batura deepakbatura@gmail.com 1 Department of Urology, London North West Healthcare NHS Trust, Ealing Hospital, Uxbridge Road, Southall, London UB1 3HW, UK 2 Department of Pathology, London North West Healthcare NHS Trust, Ealing Hospital, Uxbridge Road, Southall, London UB1 3HW, UK