Case 38, bladder biopsy with urothelial carcinoma. High power view of the epithelium. The field is slightly out of focus, the epithelial cells are dark and one cannot appreciate and detail in their nuclei. Umbrella cells are clearly visible the upper part of image, but are not present in the center and lower areas. Without umbrella cells, it might be difficult to distinguish between a benign or dysplastic epithelium. There are at least to image problems present: focus and dynamic range (lack of detail in the dark nuclei). Though nuclei can be dark for reasons not related to images (i.e. histologic staining), in this case better nuclear detail was appreciated under the microscope.