Spontaneous lingual papillomas in fischer 344 rats

Kang, Boo-hyun; Lim, Chang-hyeong

Korean Journal of Veterinary Research 1992;32(4):635-640.

¹Taxicology Research Center, Korea Research Institute of Chemical Technology
²College of Veterinary Medicine, Seoul National University

Fischer 344 랫드의 혀 유두종(Lingual papilloma) 자연발생 예

강부현¹, 임창형²

¹한국화학연구소 안전성연구센터
²서울대학교 수의과대학

Abstract

Two cases of lingual masses were observed among 500 Fischer 344 (F344) rats which were used as control and treated animals in a 2 year carcinogenicity study in Toxicology Research Center, Korea Research Institute of Chemical Technology. The masses grossly appeared as tan, pedunculated, fungiform on the dorsal aspect of the base of the tongues. They were approximately $1.5{ imes}1.2{ imes}0.3cm$ in size. The microscopic features consisted of acanthosis, hyperkeratosis, papillary projection with connective tissue cores and multifocal chronic active inflammation with hair shafts. The results observed support the epigenetic mechanism of tumorigenesis which is caused by Physical stimuli of foreign bodies. Both of the masses were diagnosed as papillomas with the incidence rate of 0.4%(1/250) in each sex on the basis of the gross and microscopic features.

Key Words: Fischer 344 rat, papilloma, spontaneous, tongue, histopathology