Nose, Epithelium - Necrosis

Image of necrosis in the nose, transitional epithelium from a female B6C3F1/N mouse in a subchronic study
Nose, Transitional epithelium - Necrosis in a female B6C3F1/N mouse from a subchronic study. The epithelial lining of a turbinate is necrotic, with evidence of exfoliation of necrotic cells.
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Image of necrosis in the nose, transitional epithelium from a female B6C3F1/N mouse in a chronic study
Nose, Transitional epithelium - Necrosis in a female B6C3F1/N mouse from a chronic study. Necrotic epithelium is characterized by prominent pyknosis, with evidence of exfoliation; acute inflammation is also present.
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Image of necrosis in the nose, transitional epithelium from a  B6C3F1/N mouse in a subchronic study
Nose, Transitional epithelium - Necrosis in a B6C3F1/N mouse from a subchronic study. There is epithelial necrosis and loss of epithelium from the nasal turbinate. Image provided courtesy of Dr. R. Miller.
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Image of necrosis in the nose, olfactory epithelium from a male F344/N rat in a subchronic study
Nose, Olfactory epithelium - Necrosis in a male F344/N rat from a subchronic study. There is loss of cells in the olfactory epithelium.
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Image of necrosis in the nose, olfactory epithelium from a female B6C3F1/N mouse in an acute study
Nose, Olfactory epithelium - Necrosis in a female B6C3F1/N mouse from an acute study. Loss of cells and cell debris is present in the olfactory epithelium. Image provided courtesy of Dr. R. Miller.
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Image of necrosis in the nose, olfactory epithelium from a male B6C3F1/N mouse in a subchronic study
Nose, Olfactory epithelium - Necrosis in a male B6C3F1/N mouse from a subchronic study. Necrosis is present in the olfactory epithelium and turbinate bone (plus inflammation).
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comment:

Epithelial necrosis ( Figure 1image opens in a pop-up window , Figure 2image opens in a pop-up window , Figure 3image opens in a pop-up window , Figure 4image opens in a pop-up window , Figure 5image opens in a pop-up window , and Figure 6image opens in a pop-up window ) a common lesion in inhalation studies, particularly with strong irritants, but may also be seen in other types of studies. A number of changes may manifest with epithelial necrosis, including pyknosis or karyorrhexis of nuclei, karyolysis, cell fragmentation, increased cytoplasmic eosinophilia, the presence of cell debris, indistinct cell outlines, and exfoliation of cells. Any of the epithelial or other cell types may be affected, and the necrosis may extend into associated structures such as the nasal glands, nasolacrimal ducts, and nasal turbinate bone ( Figure 6image opens in a pop-up window ). Loss of sensory cells in the olfactory epithelium is frequently accompanied by atrophy of the nerve bundles in the lamina propria.

recommendation:

Epithelial necrosis should be diagnosed and graded whenever present. The necrotic cells, or remnants thereof, must be present if necrosis is to be diagnosed. If necrotic cells are not present, then ulcer or erosion should be diagnosed. A site modifier (e.g., respiratory, transitional, squamous, or olfactory epithelium, vomeronasal organ, lacrimal duct) should be included in the diagnosis to indicate the location of the lesion. If the lesion is present in more than one location, it should be diagnosed separately for each location in which it is a prominent change. Necrosis may occur in the presence of other olfactory changes and should be diagnosed when present as a distinct, clearly defined entity. Necrotic lesions that are secondary to other lesions, such as inflammation, should not be diagnosed separately unless warranted by severity but should be described in the pathology narrative. Associated lesions, such as inflammatory cell infiltrate, inflammation, turbinate bone necrosis, or hemorrhage, should not be diagnosed separately unless warranted by severity.

references:

Boorman GA, Morgan KT, Uraih LC. 1990. Nose, larynx, and trachea. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, eds). Academic Press, San Diego, 315-337.

Herbert RA, Leninger JR. 1999. Nose, larynx, and trachea. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, ed). Cache River Press, Vienna, IL, 259-292.

Monticello TM, Morgan KT, Uraih LC. 1990. Nonneoplastic nasal lesions in rats and mice. Environ Health Perspect 85:249-274.
Full Text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568333/

National Toxicology Program. 1994. NTP TR-437. Toxicology and Carcinogenesis Studies of Hexachlorocyclopentadiene (CAS No. 77-47-4) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). NTP, Research Triangle Park, NC.
Abstract: http://ntp.niehs.nih.gov/go/6018

National Toxicology Program. 1999. NTP TR-490. Toxicology and Carcinogenesis Studies of Glutaraldehyde (CAS No. 111-30-8) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). NTP, Research Triangle Park, NC.
Abstract: http://ntp.niehs.nih.gov/go/10170

National Toxicology Program. 2008. NTP TR-552. Toxicology and Carcinogenesis Studies of Propargyl Alcohol (CAS No. 107-19-7) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). NTP, Research Triangle Park, NC.
Abstract: http://ntp.niehs.nih.gov/go/29275

Renne R, Brix A, Harkema J, Kittel B, Lewis D, March T, Nagano K, Pino M, Rittinghausen S, Rosenbruch M, Tellier P, Wohrmann T. 2009. Proliferative and nonproliferative lesions of the rat and mouse respiratory tract. Toxicol Pathol 37(7 suppl):5S-73S.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/20032296