title: Historical control background incidence of spontaneous thyroid and parathyroid glands lesions of rats and CD-1 mice used in 104-week carcinogenicity studies.
abstract: The incidence and range of spontaneous thyroid and parathyroid glands findings were determined in control Han-Wistar and Sprague-Dawley rats, and CD-1 mice from 104-week carcinogenicity studies carried out between 1998 and 2010 at Charles River Edinburgh. In both strains of rats and in CD-1 mice, non-proliferative lesions of the thyroid or parathyroid glands were generally uncommon apart from some findings in CD-1 mice such as ultimobranchial duct/cyst (5.72%), follicular distension/dilatation (3.84%), and cystic follicles (3.53%). In Han-Wistar rats, thyroid proliferative lesions were slightly more frequent in males than in females, but in Sprague-Dawley rats, they were of similar incidence in both sexes. The most common findings overall in Han-Wistar and Sprague-Dawley rats were C-cell hyperplasia (48.11% and 36.56%, respectively) and adenoma (10.87% and 9.52%, respectively), follicular cell hyperplasia (4.21% and 0.91%, respectively) and adenoma (4.32% and 1.36%, respectively). Secondary neoplastic lesions either in thyroid or parathyroid gland were poorly represented.
authors: Charles River Laboratories Edinburgh Ltd., Elphinstone Research Centre, Tranent, East Lothian, EH33 2NE, United Kingdom.
authors: Kaori
authors: K
authors: Isobe
authors: Charles River Laboratories Edinburgh Ltd., Elphinstone Research Centre, Tranent, East Lothian, EH33 2NE, United Kingdom.
authors: Sydney
authors: S
authors: Mukaratirwa
authors: Charles River Laboratories Edinburgh Ltd., Elphinstone Research Centre, Tranent, East Lothian, EH33 2NE, United Kingdom.
authors: Claudio
authors: C
authors: Petterino
authors: Charles River Laboratories Edinburgh Ltd., Elphinstone Research Centre, Tranent, East Lothian, EH33 2NE, United Kingdom.
authors: Alys
authors: A
authors: Bradley
keywords: CD-1; Han-Wistar; Sprague-Dawley; carcinogenicity studies; parathyroid gland; thyroid gland