Lymphocytic vasculitis of the prostate transition zone

Study Type--Pathology (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Lymphocytic vasculitis of the prostate is an exceedingly rare form of localised vasculitis that presents without systemic involvement, and is illustrated with anecdotal case reports; often as localised polyarteritis nodosa-like vasculitis. True incidence and clinical significance of lymphocytic vasculitis of the prostate in surgical specimens is virtually unknown. The present findings support that lymphocytic vasculitis of the prostate was present in 67 (12.4%) of 540 specimens. Lymphocytic vasculitis of the prostate was present in 14 (93.3%) of 15 specimens with prostatic infarction (P < 0.001) with a risk of 124.68 (OR [odds ratio]; 95% CI [confidence interval] 16.07-967.07) as compared with BPH cases not associated with lymphocytic vasculitis.

• To present our experience of lymphocytic vasculitis of the prostate in men with benign prostatic hyperplasia (BPH) without systemic involvement, as this is an exceedingly rare form of localised vasculitis and the incidence in surgical specimens and clinical significance of lymphocytic vasculitis is virtually unknown.

• A sequential cohort series of 540 surgical specimens removed because of BPH-related symptoms, including simple prostatectomy (374 men) and transurethral resection of the prostate (166), comprised the study group. • All men had histological diagnosis of BPH and received surgical therapy only. None of the men had had previous surgery or granulomatous prostatitis. • The mean (range) age at diagnosis was 67.8 (38-89) years.

• Lymphocytic vasculitis of the prostate was present in 67 (12.4 %) of 540 specimens. It was seen in a variable number of small- to medium-sized parenchyma arteries with segmental to transmural lymphocytic inflammation, within the morphological spectrum of a polyarteritis nodosa (PAN)-like lesion seen at the periphery of BPH nodules. • In four cases, focal fibrinoid necrosis was seen in vessels with otherwise typical lymphocytic vasculitis features. Immunohistochemical staining showed a T cell predominant polymorphic cellular infiltrate with a minor component of B cells and monocytes. Six cases additionally had eosinophils (<1% of inflammatory cells). • Lymphocytic vasculitis of the prostate was present in 14 (93.3%) of 15 specimens with prostatic infarction (P < 0.001) with a risk of 124.68 (odds ratio [OR]; 95% confidence interval [CI] 16.07-967.07) as compared with BPH cases not associated with lymphocytic vasculitis. Logistic regression multivariate analysis selected both lymphocytic vasculitis of the prostate and patient age as significant predictors of prostate infarction with lymphocytic vasculitis being the most significant (P < 0.001; OR 128.12; 95% CI 16.298-1007.202). Follow-up information was available in all cases, range 2-16 years, and none of the patients developed systemic disease. • A validation set of 1665 additional cases including radical prostatectomy, cystoprostatectomy, and needle biopsies showed lymphocytic vasculitis of the prostate being associated to prostate infarction on univariate and multivariate logistic regression (P < 0.001; OR 228.34; 95% CI 45.17-1154.22) analyses.

• Lymphocytic vasculitis in men with BPH is associated with prostatic infarction and should be considered a form of localised vasculitis with PAN-like morphology that does not necessitate additional evaluation for systemic disease. • The potential clinical relevance of lymphocytic vasculitis warrants further investigation.