Histopathological characteristics of interstitial cystitis/bladder pain syndrome without Hunner lesion

We aimed to assess the distinct histopathological characteristics and their clinical significance between non-Hunner and Hunner interstitial cystitis/bladder pain syndrome(IC/BPS).

We prospectively enrolled and classified IC/BPS patients, based on cystoscopic findings, as non-Hunner type IC and Hunner type IC. Specimens obtained from the posterior wall in non-Hunner type IC cases during hydrodistension or from Hunner /non-Hunner lesions in Hunner type IC cases during transurethral resection were evaluated. Stress urinary incontinence patients with microscopic hematuria were selected as controls. Biopsy specimens were obtained from 15 non-Hunner type IC, 15 Hunner type IC, and 5 non-IC patients. Severe and moderate fibrosis was more frequently observed in non-Hunner than in Hunner type IC and non-IC cases. However, severe and moderate inflammation was more frequently observed in Hunner than in non-Hunner type IC cases. The remnant urothelium was significantly decreased in Hunner than in non-Hunner type IC and non-IC cases (p<0.05), and non-Hunner type IC cases exhibited a greater number of mast cells than Hunner type IC and non-IC cases (p=0.035). Accordingly, several fibrosis promoting genes were highly expressed in bladder tissues of non-Hunner type IC, compared with Hunner type IC. Patients with severe fibrosis showed a significantly increased urinary frequency and smaller bladder capacity as compared to those with moderate and mild fibrosis (all p<0.05).

Non-Hunner type IC is characterized by severe fibrosis and increased mast cell infiltration, whereas Hunner-type IC is characterized by severe inflammation and urothelial denudation in whole bladder. Fibrosis in the bladder of IC/BPS patients was correlated with increased urinary frequency and decreased bladder capacity. This article is protected by copyright. All rights reserved.

Histopathology. 2017 Apr 10 [Epub ahead of print]

Aram Kim, Ju-Young Han, Chae-Min Ryu, Hwan Yeul Yu, Seungun Lee, YongHwan Kim, Se Un Jeong, Yong Mee Cho, Dong-Myung Shin, Myung-Soo Choo

Department of Urology, Konkuk University Hospital, Konkuk University School of Medicine, Seoul, Korea., Department of Urology, Asan Medical Center, University of Ulsan College of Medicine., Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine., Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

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