Kidney, Renal Tubule - Degeneration

Image of renal tubule degeneration in the kidney from a male Tg.Ac (FVB/N) hemizygous mouse in a subchronic study
Kidney, Renal tubule - Degeneration in a male Tg.Ac (FVB/N) hemizygous mouse from a subchronic study. The degeneration of cortical tubule epithelial cells is characterized by vacuolation of the cytoplasm and pyknosis of the nuclei.
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Image of renal tubule degeneration in the kidney from a female F344/N rat in a subchronic study
Kidney, Renal tubule - Degeneration in a female F344/N rat from a subchronic study. In this case, the degeneration is characterized by tubule cells with an eosinophilic tinctorial change and cytoplasmic vacuolation.
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comment:

Degeneration is a nonspecific entity that can arise from any number of etiologies that perturb cell function and is often an early indicator of necrosis. Degeneration, in some cases, is preceded by vacuolation ( Figure 1image opens in a pop-up window ). In general, degeneration is characterized by several morphologic and variable cell features, such as cell swelling with or without cytoplasmic vacuolation and pale-staining and fragmented cytoplasm ( Figure 2image opens in a pop-up window ). Degeneration must be distinguished from apoptosis, which represents the normal process of cell turnover in the kidney. Necrosis generally includes cell swelling, nuclear pyknosis and/or karyorrhexis, and cellular sloughing. Degeneration may be either reversible or irreversible.

recommendation:

Degeneration should be diagnosed and graded. If applicable, the location of the affected tubule(s) should be included as a site modifier in the diagnosis. Associated lesions, such as inflammation or regeneration, should not be diagnosed separately unless warranted by severity but should be described in the pathology narrative.

references:

Frazier KS, Seely JC, Hard GC, Betton G, Burnett R, Nakatsuji S, Nishikawa A, Durchfeld-Meyer B, Bube A. 2012. Proliferative and non-proliferative lesions in the rat and mouse urinary system. Toxicol Pathol 40:14S-86S.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/22637735