Squamous metaplasia in the penile urethra due to oestrogen therapy.

Histological examination was performed on the anterior penile urethra from 21 asymptomatic trans-sexual patients taking oestrogens prior to surgery. Squamous metaplasia was present in 15 of these patients and in 1 man taking progesterones. Immunohistochemical staining for oestrogen receptors in the urethra was negative. Severe squamous metaplasia was associated with patchy chronic inflammatory cell infiltration but this was also present in normal controls. The lack of recognised complications of squamous metaplasia at this site suggests that it is an incidental observation in men taking oestrogens.