Coexistence of corticotroph adenoma and thyrotroph hyperplasia in a dog.
Pituitary thyrotroph hyperplasia results from prolonged primary hypothyroidism in humans, mice and rats. In dogs with Cushing's disease, many cases have low serum thyroid hormones concentrations due to euthyroid sick syndrome. A 6-year-old castrated male Beagle diagnosed with Cushing's disease had a high serum thyroid stimulating hormone (TSH) concentration that was treated by hypophysectomy. On histological examination, the resected pituitary gland contained both a corticotroph adenoma and thyrotroph hyperplasia. The TSH-positive cell ratio in this case was greater than that of healthy Beagles. In the present case, the pituitary thyrotroph hyperplasia was probably caused by primary hypothyroidism. In conclusion, this Beagle is the first histological confirmation of the coexistence of a corticotroph adenoma and thyrotroph hyperplasia.
Teshima
Takahiro
T
Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo, Japan. teshima@bg8.so-net.ne.jp
Hara
Yasushi
Y
Shigihara
Kae
K
Takekoshi
Susumu
S
Nezu
Yoshinori
Y
Harada
Yasuji
Y
Yogo
Takuya
T
Teramoto
Akira
A
Osamura
Robert Y
RY
Tagawa
Masahiro
M
D049913:ACTH-Secreting Pituitary Adenoma / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D000236:Adenoma / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D006965:Hyperplasia / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D047748:Pituitary ACTH Hypersecretion / Q000150:complications / Q000662:veterinary*; D052684:Thyrotrophs / Q000473:pathology*