Urodynamic and histological correlates of benign prostatic hyperplasia.

The tissue obtained from transurethral prostatectomies was evaluated histologically and correlated to the clinical findings in 81 patients with benign prostatic hyperplasia. A median of 9 hematoxylin and eosin-stained tissue slides per patient were examined, each containing from 1 to 15 curettings. The patients were divided into 3 groups according to the following histology: predominantly stromal hyperplasia (39 patients), predominantly glandular hyperplasia (29 patients), and equal proportions of stromal and glandular hyperplasia (mixed group, 19 patients). There was no significant difference among the groups in patient age and duration of symptoms. The weight of resected tissue was significantly lower in the stromal group (median 16 mg.), compared to the glandular group (median 20 gm.) and the mixed group (median 25 gm.). Additionally, 29 of the 81 patients had chronic inflammation characterized by multifocal infiltrates of lymphocytes. These patients had significantly larger prostates (median 25 gm.) compared to those without lymphocytic infiltration (median 15 gm.). Sixty-five patients had a 3-month followup examination. Preoperatively there was no difference among the groups in maximum flow at uroflowmetry but at 3-month followup the stromal group had a median maximum flow of 13 ml. per second compared to 16.8 ml. per second in the glandular group and 21.5 ml. per second in the mixed group. These findings document histologically what has been reported from a clinical perspective: the clinical prostatism/benign prostatic hyperplasia complex is a spectrum of histological entities, and the small prostate with predominantly stromal hyperplasia responds less favorably to transurethral resection as determined by urodynamic evaluation.