Lower urinary tract involvement in patients with newly diagnosed autoimmune bullous dermatoses: an urethrocystoscopic study.

Introduction: To date, there are no published data assessing lower urinary tract involvement in patients with autoimmune bullous dermatoses (ABD).

Methods: Fourteen of 30 consecutive patients diagnosed with ABD between October 2007 and December 2008 consented to undergo a diagnostic video-recorded urethrocystoscopy: 9 patients (7 women and 2 men) with pemphigus vulgaris, 4 patients (2 women and 2 men) with bullous pemphigoid and 1 female patient with mucous membrane pemphigoid.

Results: None of the 14 patients complained of lower urinary tract symptoms. Urethrocystoscopy disclosed characteristic lower urinary tract lesions in almost every patient with ABD (13 of 14 patients; 93%). Two, partly overlapped, pathologic patterns prevailed: (a) nonkeratinizing squamous metaplasia (SM) found in 64% of the patients, including 2 of 4 men; (b) mucosal inflammation of the bladder base/trigone that extended-especially among male patients-to the proximal urethra (64% of the patients). SM prevailed among patients with pemphigus vulgaris, inflammatory lesions among patients with bullous pemphigoid (P = 0.003) and involvement of proximal urethra among male patients (P = 0.004), irrespective of the particular ABD diagnosis.

Conclusions: The authors present, to the best of their knowledge, for the first time in the literature, urethrocystoscopic evidence that inflammatory urothelial lesions of the bladder and proximal urethra confounded with nonkeratinizing SM of the trigone are an almost invariable finding in patients with ABD. Studies focusing on the elucidation of the pathomechanism of bladder lesions in these patients may contribute to the better understanding of both the pathophysiology of the bullous skin diseases and the pathobiology of the bladder urothelium.