A Spontaneous Ovarian Immature Teratoma in a Juvenile Rat

Abstract

A spontaneous ovarian immature teratoma characterized by the presence of tissue derivatives of endoderm, mesoderm and ectoderm was investigated histopathologically in a 6-week-old juvenile Crj:CD(SD)IGS rat. The various kinds of tissue components observed in this teratoma were mainly mature elements derived from three embryonic germ layers, such as nervous tissue, skin, pancreas, salivary gland, gastrointestinal tract, respiratory tracts, striated and smooth muscle, bone with bone marrow, cartilaginous tissue and adipose tissue. Remarkable features were that this teratoma contained immature tissues intermingled with mature tissues, which typically took the form of primitive neuroepithelial rosettes and tubules and islands of immature cartilage, showing evidence of malignancy. A small yolk sac carcinomalike focus was also observed. Neither invasion nor distant metastases were found in the other organs and tissues. This is the first report of an ovarian immature teratoma in a rat.

Highly Metastatic Ovarian Yolk Sac Carcinoma in a Rat

“…It has been reported that inducible yolk sac carcinoma is composed of endodermal cells and contains mesenchymal, trophoblastic and mesodermal cells 7,12 . Furthermore, in a previous report, a small yolk sac carcinoma-like focus was detected in a large immature ovarian teratoma in a rat 13 . From this evidence, it is considered that the tubular and cystic structures lined by goblet cells and trophoblastic giant cells in the present tumor may have resulted from differentiation or dedifferentiation of totipotential or endodermal cells.…”

Mixed Germ Cell Tumor with Embryonal Carcinoma, Choriocarcinoma, and Epithelioid Trophoblastic Tumor in the Ovary of a Cynomolgus Monkey

“…The term mixed germ cell tumor (MGCT) is commonly used in human pathology and is defined as germ cell tumors that include at least two different germ cell elements. On the other hand, in laboratory or domestic animal pathology, the term is not commonly used because the number of reported germ cell tumors including several elements is low and the definition of MGCT has not been clarified (Tsubota et al 2004). In animal pathology, embryonal carcinoma (EC) is described as a tumor composed of embryonic multipotential cells that are capable of further differentiation.…”

Ovarian teratoma displaying a wide variety of tissue components in a broiler chicken (<i>Gallus Domesticus</i>): morphological heterogeneity of pluripotential germ cell during tumorigenesis

“…Although uncommon, ovarian teratomas that are classified into a category of the germ cell tumors have been previously described in human beings (Kraus, 1977;Outwater et al, 2001;Kuno et al, 2004;Schanmughapriya et al, 2011), nonhuman primates (Baskin et al, 1982), experimental rats (Tsubota et al, 2004), and domestic animals, including horses, pigs, dogs, and cattle (Dehner et al, 1970;Gruys et al, 1976;Rodríguez et al, 1994;Basaraba et al, 1998;MacLachlan and Kennedy, 2002;Sato et al, 2003;Lefebvre et al, 2005;Schlafer and Miller, 2007;Gamba et al, 2014). Spontaneous ovarian or intraabdominal teratomas have been reported in the avian species, including chickens (Campbell and Appleby, 1966;Helmboldt et al, 1974;Gupta, 1976;Mohamed et al, 2006), ducks (Cullen et al, 1991;Bolte and Burkhardt, 2000), a goose (Reece and Lister, 1993), and a bald eagle (Ford et al, 2006).…”