ABSTRACT
The in vivo staining of the mucosa of the bladder with methylene blue is a non-invasive, technically simple investigation not stressing for the patient by means of which it is possible to gain informations about place and extension of non-papillary plan-like growing carcinomas and severe dysplasias. Apart from this by this means a coarse estimation of the degree of malignity can be done, which in every case requires the cytologic and histopathologic control. Moreover, the already resected part of the tissue can be delimited well markedly from the parts not yet resected, since wound surfaces covered with inflammatory exudate, as they are found after the first resection, get a very intensive strong staining. The in vivo staining of the mucosa of the bladder is an essential supplementation of the formerly existing diagnostic methods in tumours of the urinary bladder.