Urinary Bladder - Pigment

Image of pigment in the urinary bladder from a female F344/N rat in a chronic study
Pigment-a focal area of hemosiderin from a female F344/N rat in a chronic study.
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Pigment is rarely reported in urinary bladders of rodents. The most common pigment is hemosiderin ( Figure 1image opens in a pop-up window ). Pigmentation of urothelium has been observed with administered dye compounds.


Pigment should be diagnosed and given a severity grade. With the exception of Prussian blue staining for hemosiderin, definitive pigment identification is often difficult in histologic sections, even with a battery of special stains. Therefore, it is recommended that a diagnosis of “pigment” (as opposed to diagnosing the type of pigment, e.g., hemosiderin or lipofuscin) is more appropriate. The pathology narrative should describe the morphologic features of the pigment.


Jokinen MP. 1990. Urinary bladder, ureter, and urethra. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, 109-126.
Abstract: http://www.ncbi.nlm.nih.gov/nlmcatalog/9002563