Canine ovarian gonadoblastoma with dysgerminoma overgrowth: a case study and literature review.

BACKGROUND: Gonadoblastoma (GB) is a rare mixed germ cell-sex cord-stromal tumour, first described in humans, commonly found in dysgenetic gonads of intersex patients that have a Y chromosome. However, this entity in not recognized in the WHO classification of tumours of genital system of domestic animals. Herein, we describe a case of ovarian gonadoblastoma with proliferation of dysgerminoma and sex cord-stromal tumour components, in a phenotypically and cytogenetically normal bitch. CASE PRESENTATION: A 17-year-old cross-breed bitch had a firm, grey-white multinodular mass in the left ovary. The tumour was submitted to histopathological examination and Y chromosome detected through karyotype analysis and PCR studies. Microscopically, the ovary was almost replaced by an irregular neoplasm composed of three distinct, intermixed elements: dysgerminoma, mixed germ cell-sex cord-stromal tumour resembling human GB and a proliferative sex cord-stromal tumour component. The germ cells of gonadoblastoma and dysgerminoma components were immunoreactive for c-KIT. Sex cord-stromal cells of gonadoblastoma were immunoreactive for α-inhibin. The sex cord-stromal tumour was immunoreactive for AE1/AE3, occasionally for α-inhibin and negative for epithelial membrane antigen (EMA). The karyotype was 78, XX and PCR analysis confirmed the absence of the Y chromosome. CONCLUSION: Based on these findings, a diagnosis of gonadoblastoma with proliferation of dysgerminoma and sex cord-stromal tumour was made. This is the first case of ovarian gonadoblastoma in a female dog.

Histopathological pattern of gonads in cases of sex abnormalities in dogs: An attempt of morphological evaluation involving potential for neoplasia.

Disturbances in sex differentiation (DSD - disorder of sexual development) may result from disturbances in sex chromosomes or a disturbed development of gonads, or from genotypic disturbances. The objective of this article is to describe the histological structure of gonads in dogs showing sexual disturbances and a case of a cancer resembling gonadoblastoma in one of the animals. Among the 10 examined dogs with disturbances of sex development only a single case of a gonadoblastoma was observed. In animals with sex disturbances, similarly to humans, there exists a potential tendency for neoplastic lesions in dysgenetic gonads. As a rule, its frequency in population is confined due to the early procedure of castration of non-breeding dogs. In the present study dogs demonstrated phenotypical traits of bitches with developmental anomalies such as hyperplastic clitoris with vestigial os penis (baculum), or abnormalities in the location and structure of the vulva. The material for the study included canine gonads of various breeds, sampled from phenotypical bitches, aged 7 months to 4 years - patients of the Department of Reproduction and Clinic of Farm Animals, Faculty of Veterinary Medicine, University of Environmental and Life Sciences in Wroclaw (Poland) in years 2006-2013. The organs were surgically removed from the abdomen and sent for histopathological examination for the purpose of determining their histological structure. The 10 examined cases of altered gonads included 6 bilateral cases of testes (60%), 2 cases of bilateral ovotestis (20%), one case of co-manifestation of testis and ovotestis (10%), and a single case of a testis and a neoplastically altered gonad (gonadoblastoma) (10%).

Gonadoblastoma in the ovaries of a lesser galago (Galago senegalensis braccatus).

An enlarged right ovary was removed from a 14-year-old lesser galago (Galago senegalensis braccatus). Cytological preparations consisted of a heterogeneous population of neoplastic cells admixed with extracellular hyaline structures and cell-free nuclei. Microscopically, the ovary was replaced with gonadoblastoma and was composed of nests of germinal cells, including large oocyte-like cells, and sex cord-stromal cells arranged in palisading patterns around the germinal cells, the periphery of the nests and around extracellular hyaline material. The animal died 2 years after initial diagnosis. Necropsy examination revealed gonadoblastoma in the left ovary. The germinal cells of the tumour in the right and left ovaries were immunoreactive for calretinin, OCT3/4, PGP 9.5, Ki67 and/or faintly for cytokeratins. Sex cord-stromal cells were immunoreactive for calretinin, OCT3/4, GATA-4, E-cadherin and vimentin. Luteinized sex cord-stromal cells were immunoreactive for inhibin-alpha. The extracellular hyaline material was immunoreactive for laminin. This is the first case of gonadoblastoma in a non-human primate.

Testicular gonadoblastoma in two pet domestic rabbits (Oryctolagus cuniculus domesticus).

Testicular gonadoblastoma is an uncommon tumor in domestic animals. The current study describes a testicular gonadoblastoma in 2 pet domestic rabbits (Oryctolagus cuniculus domesticus) based on the histomorphological, immunohistochemical, and ultrastructural characteristics of the tumor. The tumor tissue consisted of discrete tubular structures separated by a fibrous stroma. The tubular structures were composed of large round cells similar in appearance to germ cells in the seminiferous tubules, and small spindle cells with oval or elongated nuclei resembling Sertoli cells. The spindle cells showed peculiar structural patterns arranged in a coronal or follicular pattern, often forming Call-Exner bodies like those in an ovarian granulosa cell tumor. One case was concomitant with seminoma. Immunohistochemistry revealed large round cells that were positive for c-kit and placental alkaline phosphatase, while spindle cells were positive for vimentin and Wilms tumor protein. Ultrastructurally, the spherical eosinophilic material (Call-Exner body) consisted of duplicated basal lamina, and sex cord components surrounded a single degenerative cell similar to a germ cell.

Bilateral gonadoblastomas in a dog with mixed gonadal dysgenesis.

Gonadoblastomas are rare mixed germ cell neoplasms, which are frequently diagnosed in testes excised for other reasons. In human patients these tumours are usually associated with undescended testes or dysgenetic gonads. This report describes a 10-year-old male dog with mixed gonadal dysgenesis ("streak testis" on the right side and testis on the left side) and bilateral gonadoblastomas. Immunohistochemical analysis revealed an atypical and mitotically active germ cell population which co-expressed placental alkaline phosphatase and c-kit oncogene, admixed with inhibin- and S-100 protein-positive sex cord cells. The findings were generally consistent with previous reports of the dual population of neoplastic cells in gonadoblastomas affecting human patients, and closely resembled the findings in the only other case reported in dogs. Moreover, the findings further support the proposal that gonadoblastomas should be considered a special form of in-situ germ cell neoplasia.