Melanosis of the Bladder: Possible Pathogenetic Mechanisms

Figure 2

Histopathological preparations of bladder mucosa showing melanosis. (a) H&E-stained section showing melanin in the urothelium. (b) Many of the pigmented urothelial cells are immunoreactive for S100 protein (red stain). (c) The melanin is shown (black) in a Masson Fontana preparation. (d) The Masson Fontana reaction is abolished by prior treatment of the section with a bleach.

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