Characteristics of mast cells in normal bladder, bacterial cystitis and interstitial cystitis.

An analysis was made of the numbers and characteristics of mast cells in lateral bladder wall biopsies from 22 patients with interstitial cystitis, 6 with bacterial cystitis and 8 normal controls, using toluidine blue stains and computerised video image analysis techniques. A significantly greater number of mast cells were found within the detrusor muscle in interstitial cystitis than in bacterial cystitis or normal controls. Within the urothelium and submucosa, mast cell numbers were significantly greater than in normal controls in both interstitial and bacterial cystitis. In interstitial cystitis mast cells were significantly larger within the detrusor than in the urothelium/submucosa and they appeared to degranulate predominantly within the superficial layers. Differential staining techniques, using long and short toluidine blue stains, failed to reveal statistically significant evidence of mast cell heterogeneity within the bladder wall in interstitial cystitis.