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  • Urinary Bladder - Necrosis

    Image of necrosis in the urinary bladder from a male F344/N rat in a chronic study
    An area of urothelial necrosis (arrow) associated with acute inflammation from a male F344/N rat in a chronic study.
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    Necrosis of the urothelium may be due to cytotoxicity, including direct chemical administration or irritation from crystals and calculi and may be associated with ulceration and inflammation. Necrosis is recognized by cellular eosinophilia and fragmentation, as well as nuclear pyknosis and karyorrhexis ( Figure 1image opens in a pop-up window ). Degeneration may precede necrosis, but degeneration by itself is infrequently diagnosed. Areas of previous necrosis can undergo regeneration and heal or result in urothelial hyperplasia.


    Necrosis of the urothelium should be diagnosed and given a severity grade. The pathologist should use his or her judgment in deciding whether or not secondary lesions associated with necrosis are prominent enough to warrant a separate diagnosis.

    related links:

    Urinary Bladder - Ulcer


    Cohen SM. 1989. Toxic and nontoxic changes induced in the urothelium by xenobiotics. Toxicol Appl Pharmacol 101:484-498.

    Cohen SM, Wanibuchi H, Fukushima S. 2002. Lower urinary tract. In: Handbook of Toxicologic Pathology, 2nd ed (Haschek WM, Rousseaux CG, Wallig MA, eds). Academic Press, San Diego, 337-362.

    Greaves P. 2012. Urinary bladder. In: Histopathology of Preclinical Studies, 4th ed. Elsevier, Amsterdam.