Epididymis, Duct - Dilation

Image of duct dilation in the epididymis from a  rat
Epididymis, Duct - Dilation. Segmental dilation of ducts in the epididymis of a rat. (Photograph courtesy of D. Creasy.)
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Image of duct dilation in the epididymis from a  rat
Epididymis, Duct - Dilation. Higher magnification of Figure 1 showing dilated ducts in the epididymis of a rat. (Photograph courtesy of D. Creasy.)
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comment:

Dilation of the epididymal ducts is an uncommon finding. The luminal diameter of the ducts varies significantly in different parts of the epididymis, and this must be taken into account when evaluating the change. The change is usually restricted to a specific segment of the epididymis. It can be test article related ( Figure 1image opens in a pop-up window and Figure 2image opens in a pop-up window ) or can be seen as an occasional cystic background finding in aging rats.

recommendation:

Ductal dilation should be recorded and graded and should be discussed in the pathology narrative if the incidence and/or severity appears to be related to chemical administration. If both epididymides are involved, the diagnosis should indicate bilateral and severity based on the more severely affected epididymis.

references:

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: http://www.ncbi.nlm.nih.gov/pubmed/22949412

Reid BL, Cleland KW. 1957. The structure and function of the epididymis: The histology of the rat epididymis. Aust J Zool 5:223-246.