ESPU Congress 2018 - Abstract Book

12 29 th CONGRESS OF THE ESPU 13:36–13:39 S1-3 (PP) TERMINAL MARKERS OF UROTHELIAL DIFFERENTIATION: A COMPARISON OF NEWBORN AND DELAYED BLADDER EXSTROPHY CLOSURES TO CONTROLS Matthew KASPRENSKI  1 , Zhiming YANG  2 , Mahir MARUF  1 , Karl BENZ  1 , Jonathan EPSTEIN  2 , Heather DI CARLO  1 and John GEARHART  1 1) Johns Hopkins Hospital, Johns Hopkins Medical Institutions, Division of Pediatric Urology, James Buchanan Brady Urological Institutions, Baltimore, USA - 2) Johns Hopkins University School of Medicine, Department of Pathology, Baltimore, USA PURPOSE There is debate in pediatric urology whether primary closure in patients with bladder exstrophy (BE) should be performed as a newborn or in the delayed setting. The authors examined expression of urothelial markers of terminal differentiation in exstrophic bladders obtained at the time of primary closure in both newborn and delayed closures. MATERIAL AND METHODS Bladder biopsies were obtained between 2012 and 2017 from 36 BE patients at the time of primary closure (10 newborn and 26 delayed closures). These specimens were compared to bladder speci- mens from normal infants (age 7 days to 3 years). Specimens underwent immunohistochemical staining for uroplakin II (UPII) and p63. Specimens were graded by a blinded pathologist using a scoring system of 0–3. RESULTS When compared to controls, delayed closures had a lower proportion of UPII grade 3 expression (0 % vs 62.5 %; p<0.001) and a higher proportion of UPII grade 0 expression (81.5 % vs 0 %; p<0.001). This trend persisted in the neonatal BE closure and control comparison. Neonatal clo- sures had a lower proportion of UPII grade 3 expression than controls (10 % vs 62.5 %; p=0.048) and higher proportion of UPII grade zero expression (40 % vs 0 %; p=0.048). When comparing delayed to neonatal closures, a higher proportion of UPII grade 0 was found in the delayed closures (81.5 % vs 40 %; p=0.013). There was no statistical difference in p63 expression scores when the three groups were compared. CONCLUSIONS The delayed closure group had decreased UPII expression compared to the control group and the newborn group, suggesting less urothelial differentiation.