Brunn's nests and glandular metaplasia: normal urothelial variants in the supramontanal prostatic urethra.

Sections of 292 transurethral prostatic resection specimens and 52 intact prostatic urethral specimens from male patients 10 to 89 years old were examined for the presence of Brunn's nests and glandular metaplasia in the urothelium of the supramontanal prostatic urethra. The complex pitted urethral mucosa at and below the verumontanum was not assessed. Either or both lesions were present focally in 211 transurethral prostatic resection specimens (72 per cent) and in 51 intact urethral specimens (97.5 per cent). Brunn's nests and glandular metaplasia consisted chiefly of transitional cells but in 47 transurethral prostatic resection cases glandular metaplasia contained prostatic acinar-type cells and in 1 case intestinal-type goblet cells were noted. Brunn's nests and glandular metaplasia were associated with inflammation in only 27 per cent of the cases and were not associated with dysplasia or urethral tumors except for 1 benign papilloma. We conclude that Brunn's nests and glandular metaplasia are so common in the supramontanal prostatic urethra that they represent normal urothelial variants in this segment of the urinary tract.