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  • Liver - Angiectasis

    Image of angiectasis in the liver from a female F344/N rat in a chronic study
    Angiectasis in a female F344/N rat from a chronic study.
    Figure 1 of 3
    Image of angiectasis in the liver from a female F344/N rat
    Angiectasis in a female F344/N rat from a diet restriction study.
    Figure 2 of 3
    Image of angiectasis in the liver from a female F344/N rat
    Angiectasis in a female F344/N rat from a diet restriction study (higher magnification of Figure 2).
    Figure 3 of 3
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    Focal and multifocal angiectasis ( Figure 1image opens in a pop-up window and Figure 2image opens in a pop-up window ) occurs spontaneously, and more frequently as animals age, but it can also be caused by chemicals such as nitrosamines. It consists of dilated sinusoidal spaces that are lined by normal-appearing endothelial cells ( Figure 3image opens in a pop-up window ). In larger dilated spaces, endothelial cells may multiply to line the dilated spaces. Hepatocytes adjacent to angiectatic spaces may be normal or slightly atrophic. Angiectasis is distinguished from cystic degeneration by the presence of erythrocytes in endothelial-lined channels. The distinction between marked cases of angiectasis and hemangioma is often unclear.


    Angiectasis should be documented and graded whenever present as an independent event but should not be diagnosed if it is associated with another lesion, such as a focus or a neoplasm. The number of dilated spaces and their degree of dilation will influence grading. Any indication of treatment-induced angiectasis should be recorded, graded, and described in the pathology narrative.


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    Haschek WM, Rousseaux CG, Wallig MA. 2010. Fundamentals of Toxicologic Pathology, 2nd ed. Academic Press, San Diego, 197-235.

    National Toxicology Program. 2010. NTP TR-557. Toxicology and Carcinogenesis Studies of ß-Myrcene (CAS No. 123-35-3) in F344/N Rats and B6C3F1 Mice (Gavage Studies). NTP, Research Triangle Park, NC.
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    Thoolen B, Maronpot RR, Harada T, Nyska A, Rousseaux C, Nolte T, Malarkey D, Kaufmann W, Kutter K, Deschl U, Nakae D, Gregson R, Winlove M, Brix A, Singl B, Belpoggi F, Ward JM. 2010. Hepatobiliary lesion nomenclature and diagnostic criteria for lesions in rats and mice (INHAND). Toxicol Pathol 38:5S-81S.
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