Urinary Bladder - Ulcer

Image of ulcer in the urinary bladder from a male B6C3F1 mouse in a chronic study
A focal ulcer of the urothelium, with inflammation of the underlying submucosa and muscularis layers, from a male B6C3F1 mouse in a chronic study.
Figure 1 of 2
Image of ulcer in the urinary bladder from a male F344/N rat in a chronic study
A focal ulcer with extensive necrosis and acute inflammation from a male F344/N rat in a chronic study.
Figure 2 of 2
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comment:

Ulcers may result from a number of etiologies, such as direct chemical exposure or as secondary lesions associated with inflammation, calculi, or tumors. Ulcers usually progress from urothelial erosions/necrosis and extend through the width of the urothelium, resulting in subepithelial hemorrhage and inflammation ( Figure 1image opens in a pop-up window and Figure 2image opens in a pop-up window ). The severity of the inflammation depends on the size and the chronicity of the ulcer. Acute ulceration may develop rapidly. Regenerative hyperplasia and/or fibrosis may be observed in chronic cases.

recommendation:

Ulcers should be diagnosed and given a severity grade. Inflammation and/or regenerative hyperplasia, when significant, should be diagnosed along with ulceration as an indicator of the chronicity of the lesion.

references:

Gopinath C, Prentice DE, Lewis DJ. 1987. The urinary system. In: Atlas of Experimental Toxicologic Pathology. Current Histopathology Vol. 13. MTP Press, Norwell, MA, 78.
Abstract: http://onlinelibrary.wiley.com/doi/10.1002/path.1711550414/abstract