Histopathologic Findings in Canine Pituitary Glands.
To optimize the histologic evaluation of hypophysectomy specimens, sections of 207 canine pituitary glands (196 postmortem, 11 hypophysectomy specimens) were reviewed. Adenohypophyseal proliferation was the most common (n = 79) lesion. Proliferative lesions were sparsely to densely granulated; the granules were usually basophilic to chromophobic and periodic acid-Schiff-positive. Adenohypophyseal proliferation was classified as hyperplasia (n = 40) if ≤2 mm diameter with intact reticulin network, as microadenoma (n = 22) for 1-5 mm homogeneous nodules with lost reticulin network, or as macroadenoma (n = 17) for larger tumors. Craniopharyngeal duct cysts were common incidental lesions and the only lesion in 15 dogs. Uncommon diagnoses included lymphoma (n = 4), hemorrhagic necrosis (n = 4), metastatic carcinoma (n = 3), hypophysitis (n = 3), ependymoma (n = 2), craniopharyngioma (n = 2), and 1 case each of metastatic melanoma, pituicytoma, gliomatosis, germ cell tumor, meningioma, and atrophy. The pituitary histologic diagnosis was associated with hyperadrenocorticism (HAC; P < .001) and adrenocortical histologic diagnosis ( P = .025). Both HAC and adrenocortical hyperplasia showed a positive trend with the degree of adenohypophyseal proliferation. The association of adrenocortical hyperplasia with HAC was not significant ( P = .077). Dogs with adenohypophyseal proliferations were older than dogs with normal pituitary glands ( P < .05). Brachycephalic breeds were overrepresented among dogs with pituitary macroadenoma or craniopharyngeal duct cysts, but the association was not statistically significant ( P = .076). Adenohypophyseal hyperplasia was more common than adenoma among postmortem specimens, but was unexpected in >80% of cases. Pituitary macroadenoma was the most common diagnosis in hypophysectomy specimens.
['Miller|Margaret A|MA|', 'Bruyette|David S|DS|', 'Scott-Moncrieff|J Catharine|JC|', 'Owen|Tina Jo|TJ|', 'Ramos-Vara|José A|JA|', 'Weng|Hsin-Yi|HY|', 'Vanderpool|Andrea L|AL|', 'Chen|Annie V|AV|', 'Martin|Linda G|LG|', 'DuSold|Deidre M|DM|', 'Jahan|Sina|S|']
D000818:Animals D004283:Dog Diseases D004285:Dogs D005260:Female D007016:Hypophysectomy D008297:Male D047748:Pituitary ACTH Hypersecretion D010900:Pituitary Diseases D010902:Pituitary Gland D010903:Pituitary Gland, Anterior D010911:Pituitary Neoplasms D012189:Retrospective Studies
dogs hyperadrenocorticism adenohypophyseal hyperplasia pituitary adenoma pituitary-dependent hypercortisolism transsphenoidal hypophysectomy