Fluorescence urethroscopy following instillation of 5-aminolevulinic acid: A new procedure for detecting clinical and subclinical HPV lesions of the urethra

OBJECTIVE: To report early clinical experience with intraurethral instillation of 5-aminolevulinic acid (ALA) for the detection of clinical lesions (condyloma acuminata) and subclinical human papillomavirus (HPV) lesions of the urethra, not visible by conventional endoscopy. SUBJECTS AND SETTING: Eighty-four men with clinical diagnosis of condyloma acuminata were examined for urethral HPV lesions at the Department of Urology, Ludwig Maximilian University, Munich, Germany. METHODS: The anogenital areas of the patients were thoroughly examined using a magnifying glass before and after application of 5% acetic acid. Conventional as well as fluorescence urethroscopy were performed 1 h after topical application of 0.1% ALA for 15 min. A sensitive colour charge-coupled device camera for fluorescence video inspection was used with spectral analysis. Biopsies were taken for histological examination and HPV detection by polymerase chain reaction (PCR). RESULTS: Forty-three of 84 men attending our clinic for condyloma acuminata had clinical HPV lesions of the urethra. Condylomas of the proximal urethra were found by conventional endoscopy in eight patients. Fluorescence urethroscopy detected additional subclinical lesions in 13 men. All lesions were HPV infections of the urethra confirmed histologically or by PCR. In nine of these subclinical urethra lesions low-risk HPV types (HPV6, 11, 34) were found. Four lesions were associated with high-risk types (HPV18, 31,52,58). CONCLUSIONS: Fluorescence urethroscopy is a promising diagnostic procedure for detecting subtle clinical and subclinical HPV lesions of the urethra, that are normally not visualized by conventional endoscopy. Generally, urethroscopy is recommended in all cases of externally visible condylomas of the urethra after therapy.