Spontaneous Hypertrophic Foci of Pancreatic Acinar Cells in CD Rats

A study was conducted to determine the spontaneous occurrence of hypertrophic foci of the pancreatic acinar cells in rats. Tissues from untreated control rats, 4 to 27 months of age and used in either subchronic and chronic feeding toxicity or carcinogenicity studies were reviewed. The lesions, morphologically distinctly different from nodular hyperplasia or hyperplastic nodules and adenomas, were microscopic in size and occurred in 109 of 607 males (17.6%) and 87 of 517 females (16.8%). The overall incidence of hypertrophic foci in the pancreas from rats of both sexes significantly increased with age. The lesion was not sex-related. Neither the size nor the number of lesions appeared to increase with age. The lesion represents a distinct pathologic entity and is considered to be neither hyperplastic nor neoplastic.