イヌの膀胱腫瘍における自然史の病理組織学的検討 ： Ⅰ.加齢イヌの膀胱粘膜上皮の病理組織学的検討

Abstract

Apparently normal urinary bladder of beagle dogs of both sexes were examined histopathologically. Materials were obtained from fifty autopsied aged beagle dogs and six autopsied young beagle dogs. Changes of urinary bladder epithelium were classified into five types : Brunn's nest, squamous metaplasia, lymphocytic infiltration, epithelial hyperplasia, and atypia. Brunn's nests in aged dogs were found at all ages and in both sexes. Squamous metaplasia in aged dogs was found in 25.0 per cent of males and 50.0 per cent of females. Scattered lymphocytic infiltration in aged dogs could be observed in 18.0 per cent of both sexes. Epithelial hyperplasia and atypia in aged dogs were found in 82.0 per cent and 28.0 per cent of cases, respectively ; however, no difference between sexes was found. Sites of predilection for Brunn's nests were the trigone and anterior wall ; however, those for other types of lesion were not found. As for young dogs, Brunn's nests were found in 66.7 per cent of both sexes，and sites of predilection were the trigone and anterior wall ; the other lesions were not observed. These chronic changes of urinary bladder epithelium in aged beagle dogs should be considered in the bladder carcinogenesis and natural history of bladder tumor in dogs.