Squamous metaplasia of the trigone in women with recurrent cystitis syndrome.

Urocystic mucosal biopsies of the white patch on the trigone in 44 women complaining of dysuria and frequency with or without bacteriuria showed varying degrees of squamous metaplasia as well as submucosal fibrosis. The patients with more frequent episodes of such symptoms in the past had more severe squamous metaplasia with submucosal fibrosis. Introital bacteria were found in almost all patients with mild or moderate development of squamous metaplasia, but not in those with severe lesions. These facts suggest that introital bacteria may be one of the causative factors for the initiation and early development of these abnormal mucosal changes. However, the further progression to severe mucosal alteration seems to be independent of any bacteria and this severe mucosal alteration may result in recurrence of such symptoms.