SCANNING ELECTRON MICROSCOPIC OBSERVATIONS OF THE NORMAL TRANSITIONAL CELL EPITHELIUM AND TRANSITIONAL CELL CARCINOMA OF THE URINARY BLADDER

Abstract

The scanning electron microscopy has recently been proved by Jaques et al. to be an excellent method for examining the surface structure of soft tissues. This method, by its advantages of visualization of depth and three dimensional viewing, will make it possible to observe fine surface structure of normal and pathological tissues.
In the field of urology, the paper dealing with the study of the normal resting and stretched urethra and bladder mucosa by Lloyde-Davis et al. is one of a few available publications. The technique has been applied to the tumor pathology of the urinary tract by Fulker et al. who observed proliferative human bladder epithelium and bladder tumors.
In the present study, normal and neoplastic materials of the human urinary bladder were obtained at the time of surgery. The specimens were fixed in 10% neutral formalin, dehydrated with graded alcohols and dipped in aceton, subsequently dried in air, coated with gold and examined by JSM-U3 and JSM-S1 type scanning electron microscope. All the tissues were also studied by light microscopy to ascertain histopathological identification.
By means of the scanning electron microscopy, the individual normal transitional cells were observed to be protruding mamillary and uniform in arrangement and size. The intercellular folds were clearly observed (Fig. 1. 2. 4.). All over the surface of the cells, fine granular processes were diffusely and homogenously distributed in 3000 times of magnification (Fig. 3. 5).
In the distended normal epithelium, cellular protrusions and cellular junctions were observed stretched in the distended direction and normal mamillary cellular protrusions were unable to be observed. Lacerations were discerned, while the intercellular digitations were scarcely maintained as fine threadlike structures (Fig. 6-8).
In the examination of the transitional cell carcinoma, surface of the tissues looked rather smooth at lower magnifications and intercellular folds were prominent (Fig. 9. 10. 13). The sizes of cell surface in tumors were varied more widely than those of normal cells. At high magnification, cellular details and cellular junctions could be discerned and the surface of each cell was characterized by fine granular projections (Fig. 11. 12. 14-16). On the surface of high graded tumors, there were many necrotic spots and patches of destructed cell layer.
The specimens used for the scanning electron microscopy were reexamined by ordinary transmission electron microscope and the photographs were compared with those of routine electron microscopy originally prepared. Destruction and shrinkage of the tissues possibly caused by the fixation and dehydration of the materials were revealed (Fig. 17. 18). Therefore, the interpretation of the surface structure in the scanning electron microscopy must be carefully undertaken.
The present study proves that the scanning electron microscopy provides an excellent method for morphological approach to the surface structure of normal and pathological varieties of the urothelium and the tumor formation.