Lymphocytic Hypophysitis in a Dog with Diabetes Insipidus

• Published in: Journal of comparative pathology 2012-11, Vol.147 (4), p.503-507
• Main Authors: Meij, B.P., Voorhout, G., Gerritsen, R.J., Grinwis, G.C.M., Ijzer, J.
• Format: Article
• Language: English
• Subjects: Adenoma; Adrenocorticotropic hormone; Adrenocorticotropic Hormone - metabolism; alpha-melanocyte-stimulating hormone; alpha-MSH - metabolism; Animals; anterior pituitary; Antidiuretic Agents - therapeutic use; Biopsy; Computed tomography; corticotropin; Deamino Arginine Vasopressin - therapeutic use; Desmopressin; Diabetes insipidus; Diabetes Insipidus - pathology; Diabetes Insipidus - therapy; Diabetes Insipidus - veterinary; dog; Dog Diseases; Dogs; Euthanasia, Animal; exercise; Fatal Outcome; Growth hormone; Growth Hormone - metabolism; Hair; Hormones; humans; hypophysectomy; hypophysitis; Hypopituitarism - metabolism; Hypopituitarism - pathology; Hypopituitarism - therapy; Hypopituitarism - veterinary; hypothalamus; Insulin-like growth factor I; Intolerance; Lymphocytes - pathology; Lymphocytes T; Male; Neuroendocrine Cells - metabolism; Neuroendocrine Cells - pathology; Physical training; Pituitary; Pituitary (anterior); Pituitary Gland, Anterior - metabolism; Pituitary Gland, Anterior - pathology; Polydipsia; Polyuria; somatotropin; T-lymphocytes; Thyroid-stimulating hormone; thyrotropin; Thyroxine
• ISSN: 0021-9975; 1532-3129
• DOI: 10.1016/j.jcpa.2012.04.006

An 8-year-old male German longhaired pointer was referred for diabetes insipidus responsive to treatment with desmopressin. The dog had polyuria and polydipsia, exercise intolerance and a dull hair coat. Plasma concentrations of thyroid-stimulating hormone, thyroxine, growth hormone (GH) and insulin-like growth factor-1 were decreased; plasma adrenocorticotropic hormone (ACTH) was slightly elevated and plasma α-melanocyte-stimulating hormone (MSH) was within the reference range. Computed tomography revealed a heterogeneously contrast-enhancing pituitary mass compressing the hypothalamus. Transsphenoidal hypophysectomy was performed and microscopical examination of the surgical biopsy samples revealed hypophysitis without evidence of pituitary adenoma. The hypophysitis was characterized by marked lymphocytic infiltration of the adenohypophysis that contained a mixed population of neuroendocrine cells expressing GH, ACTH or α-MSH. The lymphocytes were identified as T cells, resulting in a final diagnosis of lymphocytic hypophysitis strongly resembling human primary lymphocytic hypophysitis.