An improved and simplified method for combined light and scanning electron microscopy in human urinary cytology

Human bladder-washing and voided urine specimens from normal cases and inflammatory and malignant lesions were examined by the combined use of light microscopy (LM) and scanning electron microscopy (SEM). A newly-designed mesh, which consisted of a piece of gelatin-covered, osmium-impregnated and poly-L-lysine-coated glass slide, 0.85 mm in thickness and containing 42 compartments of 25 sq mm in size, was used in this study. This mesh permitted a direct correlation of LM and SEM images, thus shortening the time of observation of specimens under SEM. With SEM, the diagnosis of malignant exfoliated urothelial cells depended on the presence or absence of pleomorphic microvilli. The technique has enhanced the accuracy of diagnosis over conventional methods, especially for noninvasive, low-grade, papillary tumors of the urinary bladder.