[Fluorescence cytology of the urinary bladder]

5-aminolevulinic acid induced fluorescence cystoscopy is invaluable for diagnosing urinary bladder carcinoma and its precursors. Because neoplastic cells of the urinary bladder possess striking fluorescent properties due to protoporphyrin IX, we initiated a study to evaluate the use of fluorescence microscopy in urinary sediments. In 27 patients suspected of having bladder carcinomas, we instilled 5-aminolevulinic acid into their urinary bladders before transurethral therapy and compared thereafter our studies of standard cytological sediments with those made under fluorescence microscopy. The results of fluorescence cystoscopy and those using urinary sediments for neoplastic cells under fluorescence microscopy correlated extremely well. In this pilot study using fluorescence microscopy, we found that we could diagnose with precision urinary neoplasms of different grades of differentiation. Accordingly, we regard fluorescence microscopy as a valuable complement for standard urinary cytology, especially since with fluorescence microscopy we can readily recognize fluorescing cells of highly differentiated urinary tumors and flat premalignant dysplasias.