PURPOSE: Guidelines of the European Society for the Study of Interstitial Cystitis identify mast cell infiltrates of detrusor muscle as a diagnostic criterion for bladder pain syndrome/interstitial cystitis, but elevated mast cells are also characteristic for overactive bladder syndrome.
The lack of uniformity in mast cell detection methods hampers comparison of data. Using state-of-the-art techniques, we investigated if mast cells differ among bladder conditions.
MATERIALS AND METHODS: Bladder biopsies from 56 patients (31 bladder pain syndrome/interstitial cystitis with (12) and without (19) Hunner's lesions, 13 overactive bladder syndrome, and 12 without bladder symptoms) were analyzed for quantity, location, distribution and activation of mast cells using immunohistochemistry with anti-mast cell tryptase. Patients were allocated to study groups by key bladder symptoms commonly used to define conditions (pain, major urgency).
RESULTS: Subepithelial mast cell localization (p< 0.001) and elevated detrusor mast cells (p=0.029) were characteristic for bladder pain syndrome/interstitial cystitis with Hunner's lesion. The optimal cutoff of 32 detrusor mast cells/mm2reached an accuracy level of only 68% (38% positive predictive value). No difference between bladder pain syndrome/interstitial cystitis without Hunner's lesion and overactive bladder syndrome was observed. Differences between the patient groups were found in lymphocytic infiltration (p=0.001), nodular lymphocyte aggregates (p< 0.001), and urothelial integrity (p< 0.001).
CONCLUSIONS: Subepithelial mast cell distribution was characteristic for bladder pain syndrome/interstitial cystitis with Hunner's lesions. Detrusor mastocytosis had a poor predictive value for bladder pain syndrome/interstitial cystitis, and mast cell assessment did not distinguish bladder pain syndrome/interstitial cystitis without Hunner's lesion from overactive bladder syndrome.
Written by:
Gamper M, Regauer S, Welter J, Eberhard J, Viereck V. Are you the author?
Department of Gynecology and Obstetrics, Cantonal Hospital Frauenfeld, Frauenfeld, Switzerland; Institute of Pathology, Medical University Graz, Austria.
Reference: J Urol. 2015 Jan 14. pii: S0022-5347(15)00057-9.
doi: 10.1016/j.juro.2015.01.036
PubMed Abstract
PMID: 25596361