title: Distinguishing cystic degeneration from other aging lesions in the adrenal cortex of Sprague-Dawley rats.
abstract: Cystic degeneration of the adrenal cortex is a common age-related finding in the Sprague-Dawley (SD) rat strain occurring more frequently in females. Compression of the adjacent cortex, a common hallmark of benign adrenal cortical tumors, often accompanies foci of cystic degeneration, creating a diagnostic challenge. Accurately differentiating these relatively common degenerative changes from proliferative lesions is critical in safety assessment studies. Cystic degeneration typically arises in the zona fasciculata of the adrenal cortex and often causes compression along the margin of the lesion. The degenerating cells are large, with abundant eosinophilic cytoplasm, or contain clear cytoplasmic vacuoles. Mitotic figures are generally uncommon. In many cases, cystic degeneration appears to arise in areas of hypertrophy in the zona fasciculata. In contrast, adrenal cortical hyperplasia and adrenal cortical adenoma are frequently comprised of smaller cells that cause compression of adjacent cortex, and in some cases mitotic figures are observed. Cytological detail and growth patterns should be considered more useful criteria than compression alone for separating degenerative cystic lesions from proliferative lesions in the adrenal cortex of SD rats.
authors: Nonclinical Safety Assessment, Covance Pharmaceutical R&D (Shanghai) Co. Ltd., Shanghai, China victoria.laast@covance.com.
authors: Victoria A
authors: VA
authors: Laast
authors: Nonclinical Safety Assessment, Covance Laboratories, Inc., Chantilly, Virginia, USA.
authors: Thomas
authors: T
authors: Larsen
authors: Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, USA.
authors: Neil
authors: N
authors: Allison
authors: National Institute of Environmental Health Sciences, National Toxicology Program, Research Triangle Park, North Carolina, USA.
authors: Mark J
authors: MJ
authors: Hoenerhoff
authors: Nonclinical Safety Assessment, Covance Laboratories, Inc., Chantilly, Virginia, USA.
authors: Gary A
authors: GA
authors: Boorman
mesh_terms: D000302:Adrenal Cortex / Q000473:pathology*; D000303:Adrenal Cortex Diseases / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology; D000306:Adrenal Cortex Neoplasms / Q000175:diagnosis / Q000473:pathology; D000375:Aging; D000818:Animals; D003560:Cysts / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology; D004195:Disease Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: Sprague-Dawley rat; adrenal cortex; aging lesions.; cystic degeneration