Granulomatous prostatitis is an inflammatory condition of the prostate that histologically features the presence of granulomas. It is subclassified as infectious granulomas, nonspecific granulomatous prostatitis, postbiopsy granulomas, and systemic granulomatous prostatitis.
Rarer forms of granulomatous prostatitis include xanthogranulomatous prostatitis and sarcoidosis. Xanthogranulomatous prostatitis is histologically similar to granulomatous prostatitis, the main difference being the prominence of foamy histiocytes, which constitute the xanthomatous component.
In mycobacterial prostatitis, granulomas predominate within the peripheral zone of the prostate, although the transition or central zone may also be affected. Small suburethral granulomas are almost always present as well.
Nonspecific granulomatous prostatitis and xanthogranulomatous prostatitis may occur in the transition and peripheral zones, whereas postbiopsy granulomatous prostatitis occurs around the resection site and along the biopsy tract. The granulomas in systemic granulomatous conditions may be centered on blood vessels.