Mast cell activation in sterile bladder and prostate inflammation (With 1 color plate)

Sterile inflammation of the bladder has often been associated with interstitial cystitis (IC), a uro-logic condition of unknown etiology, predominantly affecting young and middle-aged females, for which no effective therapy is known. Recent reports have indicated that IC is associated with an increased number of bladder mast cells. Here we report the case of a middle-aged man with chronic sterile hematuria, dysuria and lower abdominal pain associated with a high number of bladder and prostate mast cells. Following therapeutic transurethral resection of the trigone area, bladder neck and prostate, samples of bladder and prostate were examined with light and electron microscopy and contained many mast cells (about 150 cells/mm2) which were not degranulated. Nevertheless, mast cells contained many altered granules and urinary levels of histamine were elevated, implying secretion without exocytosis. These findings are discussed in the context of the pathophysiology of IC and possible therapeutic interventions.