[Scanning electron microscopy studies of the surface structure of benign and differentiated, tumorous papillary...

Surgical biopsy specimens from the urinary bladder revealing normal histological structures in 2 cases, inflammatory lesions in 4 cases, papillomas--according to WHO classification criteria--in 7 cases, and differentiated non-invasive papillary transitional cell carcinomas in 7 cases, were investigated by means of scanning electron microscopy, with regard to diagnostic surface characteristics. The preparing method using paraffinembedded tissue blocks for the retrospective study proved to be suitable for the visualization of the different surface structures known from the literature. Some of the observed surface alterations seemed to be associated with both inflammatory and neoplastic urothelial lesions. A change of the surface structure is, however, of limited diagnostic relevance, since only the quantitative distribution pattern of single characteristics points to a certain entity. Especially the appearance of pleomorphic microvilli failed to be a hallmark of malignant growth. The role of REM among other methods in the diagnostics of urothelial lesions is discussed.