Lung - Inflammation



















comment:
Inflammation of the lungs is one of the most common lesions seen in inhalation studies. In NTP studies, there are five standard categories of inflammation: acute, suppurative, chronic, chronic active, and granulomatous. In acute inflammation ( Figure 1



















A test agent may stimulate epithelial cells and resident macrophages to secrete cytokines, thus inducing an inflammatory response. Alternatively, a test agent may cause tissue damage, which secondarily results in inflammation. Several compartments within the lung may be inflamed, including the airways (bronchi and bronchioles), the alveoli or alveolar septa (interstitium), the terminal bronchiole/alveolar duct region (acinar region), perivascular areas, and the pleura. Occasionally, focal, minimal inflammation in the lung is seen as a background lesion in mice and rats ( Figure 9


recommendation:
Whenever present, Lung - Inflammation should be diagnosed and assigned a severity grade. A site modifier (e.g., perivascular, interstitial, bronchial, bronchiolar, pleural, or subpleural) should be included in the diagnosis to indicate the location of the lesion. Also, the type of inflammation (e.g., acute, chronic) should be included in the diagnosis as a modifier. If the inflammation affects more than one site, the site modifier may be omitted and the affected locations identified in the pathology narrative. The term "inflammation" should be used when the inflammatory cells are accompanied by other changes indicative of inflammation, such as vascular changes (which may result in hemorrhage or edema), necrosis or degeneration of cells, or disruption of the normal architecture. Lesions that are considered part of the inflammatory process, such as edema and hemorrhage, need not be diagnosed separately unless warranted by severity but should be described in the narrative. Necrosis or degeneration of cells may be primary, inciting an inflammatory response, or it may be secondary to the inflammation. Therefore, it can be very difficult to determine which lesion (necrosis or inflammation) is primary and which is secondary. The pathologist should use his or her judgment in determining whether to diagnose these lesions separately or to combine these related lesions into a single diagnosis. If they are combined into a single diagnosis, all components of the lesions should be thoroughly described in the narrative. A small, focal accumulation of inflammatory cells with no other evidence of inflammation (e.g., edema, hemorrhage, cell swelling, degeneration, or necrosis, alveolar septal thickening, fibrin deposition), should be diagnosed as "infiltration cellular" rather than inflammation. When present as a secondary finding to a neoplasm, the inflammation need not be diagnosed separately but should be described in the pathology narrative.related links:
Lung - Infiltration cellular, Histiocytereferences:
Boorman GA, Eustis SL. 1990. Lung. In: Pathology of the Fischer Rat: Reference and Atlas (Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, eds). Academic Press, San Diego, CA, 339-367.
Dixon D, Herbert RA, Sills RC, Boorman GA. 1999. Lungs, pleura, and mediastinum. In: Pathology of the Mouse: Reference and Atlas (Maronpot RR, Boorman GA, Gaul BW, eds). Cache River Press, Vienna, IL, 293-332.
Dungworth DL, Ernst H, Nolte T, Mohr U. 1992. Nonneoplastic lesions in the lungs. In: Pathobiology of the Aging Rat (Mohr U, Dungworth DL, Capen CC, eds). ILSI Press, Washington, DC, 143-160.
Plopper CG, Dungworth DL. 197. Structure, function, cell injury and cell renewal of bronchiolar and alveolar epithelium. In: Lung Carcinomas (McDowell EM, ed). Churchill Livingstone, Edinburgh, 94-128.
Renne, R, Brix A, Harkema J, Herbert R, Kittle 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(suppl):5S-73S. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/20032296
Web page last updated on: December 07, 2015