U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Skip to Main Navigation
Skip to Page Content
Skip to Atlas Navigation

Testis - Pigment

Image of pigment in the testis from a male B6C3F1 mouse in a chronic study
Testis - Pigment in a male B6C3F1 mouse from a chronic study. Intracytoplasmic accumulation of ceroid (lipofuscin) pigment (arrows) in interstitial cells.
Figure 1 of 2
Image of pigment in the testis from a male B6C3F1 mouse in a chronic study
Testis - Pigment in a male B6C3F1 mouse from a chronic study (higher magnification of Figure 1). Accumulation of ceroid (lipofuscin) pigment (arrows) in the cytoplasm of interstitial cells.
Figure 2 of 2
next arrow


The pigment in the testis shown in Figure 1image opens in a pop-up window and Figure 2image opens in a pop-up window represents intracytoplasmic accumulation of ceroid pigment (lipofuscin), which is a light brown, finely granular lipid-derived pigment. This can occasionally be seen as an incidental finding in the interstitial cells and may be associated with degenerative changes. Another pigment that may be seen as a consequence of hemorrhage is hemosiderin. Lipofuscin stains positively with Periodic acid-Schiff and with Schmorl’s stain, whereas hemosiderin stains with Perls’ stain.


Pigment should be diagnosed and given a severity grade. If present in both testes, it should be designated as bilateral with severity based on the more severely affected testis. 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 most appropriate. The pathology narrative should describe the morphologic features of the pigmentation. Not all pigments have to be diagnosed, as some are ubiquitous in aging animals or related to some other disease process and not toxicologically meaningful. The pathologist should use his or her judgment in deciding whether or not secondary deposits of pigment are prominent enough to warrant a separate diagnosis.


Creasy D, Bube A, de Rijk E, Kandori H, Kuwahara M, Masson R, Nolte T, Reams R, Regan K, Rehm S, Rogerson P, Whitney K. (2012). Proliferative and nonproliferative lesions of the rat and mouse male reproductive system. Toxicol Pathol 40:40S-121S.
Abstract: https://doi.org/10.1177/0192623312454337

Giannessi F, Giambelluca MA, Scavuzzo MC, Ruffoli R. 2005. Ultrastructure of testicular macrophages in aging mice. J Morphology 263:39-42.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/15536646