Value of in vivo mucosa-staining test with methylene blue in the diagnosis of pretumoral and tumoral lesions of the bladder.

An in vivo staining test, methylene blue was applied to 50 patients with bladder tumor. 378 biopsies were performed in 85 areas stained with methylene blue and in 293 random biopsy areas. Of these samples, 56 had carcinoma in situ: 38 of these were not stained (68% false-negative) and the remaining 18 took up the stain. In the latter corresponding to 11 patients, carcinoma in situ was also shown in unstained areas examined by random biopsies. In 37 areas with urothelial dysplasia, 31 were not stained (84% false-negatives) while 6 cases (16%) took up the stain. Bladder tumors were stained in an irregular way but the intensity of the stain was related to the tumor grade. According to our experience the in vivo staining test with methylene blue cannot be used as a marker for pretumoral and tumoral lesions of the bladder.