title: Histomorphological and immunohistochemical characterization of equine granulosa cell tumours.
abstract: Benign (n=33) and malignant metastasizing (n=1) granulosa cell tumours (GCTs) from 34 mares aged 3-21 years, and normal (control) ovaries from nine mares aged 3-10 years, were examined histologically and immunohistochemically (for inhibin alpha, glutathione S-transferase alpha [GSTalpha], c-erbB-2 oncoprotein [cerb], cytokeratin, vimentin, desmin and alpha-actin), the results being related where appropriate to clinical signs and endocrinological data. Availability permitting, serum samples from GCT-affected mares before and several weeks after ovariectomy were examined for the following hormones: oestradiol, progesterone and testosterone (by radioimmunoassay); and inhibin B (by a cross-reactive ELISA). Histological examination revealed that the GCTs were predominantly well differentiated neoplasms. The metastasizing GCT differed immunohistochemically from the benign GCTs in respect of the expression patterns of vimentin, cerb and GSTalpha in the granulosa cells. A notable feature was the presence of Leydig-like cells in mares with stallion-like behaviour or elevated serum testosterone, or both. GSTalpha immunolabelling indicated that the Leydig-like cells were potential producers of steroid hormone. From the immunohistochemical and endocrinological findings it was concluded that GCTs produce abnormally high concentrations of inhibin, which reduce the release of follicle-stimulating hormone, leading to atrophy of the contralateral ovary-a finding in 27 of the mares.
authors.affiliation: Institute of Pathology, Faculty of Veterinary Medicine, University of Leipzig, Germany. ellenber@rz.uni-leipzig.de
authors.forename: C
authors.initials: C
authors.lastname: Ellenberger
authors.forename: C P
authors.initials: CP
authors.lastname: Bartmann
authors.forename: H-O
authors.initials: HO
authors.lastname: Hoppen
authors.forename: J
authors.initials: J
authors.lastname: Kratzsch
authors.forename: H
authors.initials: H
authors.lastname: Aupperle
authors.forename: E
authors.initials: E
authors.lastname: Klug
authors.forename: D
authors.initials: D
authors.lastname: Schoon
authors.forename: H-A
authors.initials: HA
authors.lastname: Schoon
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D006106:Granulosa Cell Tumor / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D006734:Horse Diseases / Q000378:metabolism / Q000473:pathology*; D006736:Horses; D007124:Immunoenzyme Techniques / Q000662:veterinary*; D007265:Inhibins / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D010052:Ovariectomy / Q000662:veterinary; D010053:Ovary / Q000378:metabolism / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D012739:Gonadal Steroid Hormones; D007265:Inhibins