obtained from the operating theatre database. Patients were divided by indication (retention/ LUTS). Clinical data and histology reports were then reviewed and bivariate and logistic regression used to compare the pathological features between these groups. RESULTSOf 406 patients, 374 had evaluable data; 70% of men with urinary retention had ACI, vs 45% of those with LUTS ( P < 0.001). On logistic regression, the pathological factors associated with TURP for acute retention compared to that for LUTS were ACI, old age, and resection weight to a lesser degree. CONCLUSIONInflammation appears to be important in the pathogenesis and progression of BPH. In this study, the risk of urinary retention due to BPH was significantly greater in men with ACI than in those without, and the association of TURP for retention with ACI was stronger than that with prostate weight. This finding might offer new avenues for the medical treatment of men with LUTS due to BPH.