Background Urate crystals have been recognized anecdotally in a long list of nonarticular tissues but have not, to our knowledge, been sought or found in inflamed prostate glands. Like gouty arthritis, chronic prostatitis affects middle-aged and older men, and the prostate is often exposed to reflux of highly concentrated uric acid within the urine. Such reflux may be a trigger for inflammation within the prostate, and higher urate levels within prostatic secretions have been correlated with symptoms of chronic prostatitis (1). A single placebo-controlled study found that allopurinol decreased prostatic urate secretion and improved subjective pain (2). Should uric acid diffuse into prostatic tissue, it would reionize to urate and might well precipitate as sodium urate crystals.
Objectives To examine prostate tissue for urate crystals and correlate with degree of inflammation.
Methods Frozen unstained prostate sections were obtained from twenty consecutive radical prostatectomies in men (age 59.5 +/- 6.6) with prostate cancer. None had known hyperuricemia or gout. Non-malignant regions were examined with polarizing microscopy. H&E stained serial sections were examined independently in a blinded fashion, and inflammatory foci were graded from 1-4 based on number of mononuclear infiltrates.
Results Acicular negatively birefringent crystals were abundant in eleven specimens. Additionally, positively birefringent, sometimes rhomboidal crystals, were often observed. By severity of inflammation, crystals were seen in 4 of the 6 grade 1 specimens, 2 of 6 grade 2 specimens, 4 of 6 grade 3 specimens, 1 of 2 grade 4 specimens. All specimens contained mononuclear inifiltrates, four with polymorphonuclear cells, one with giant cells.
Conclusions Chronic prostatitis is a common problem that often frustrates patients and physicians alike. Worldwide prevalence has been estimated at ∼10% of adult men (3),(4). The etiology is unknown, and convincing evidence for effective management with antibiotics, alpha blockers, anti-inflammatories is lacking. If our preliminary findings of abundant crystals within the prostate are confirmed with further studies, then more rational therapy becomes possible with long-term urate lowering agents and anti-inflammatory drugs known to be effective in microcrystalline disease. More work is needed to precisely identify the type or types of crystal that we have found. Finally, our specimens were taken from prostate cancer patients, but our study provides no evidence to suggest a causal connection between crystals and malignancy.
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Disclosure of Interest J. Park Grant/research support from: Takeda, M. Roudier: None Declared, L. Chery: None Declared, P. Simkin Grant/research support from: Takeda