Highly Metastatic Ovarian Yolk Sac Carcinoma in a Rat

Abstract

We investigated a highly metastatic ovarian yolk sac carcinoma in a 52-week-old female Crl:CD(SD) rat. Macroscopically, the present case had severe ascites, bilateral ovarian masses and numerous nodules in the abdominal and thoracic cavities. Histopathologically, these masses and nodules were generally composed of two types of cells mimicking a parietal and visceral yolk sac. The parietal cells were round to polygonal, contained eosinophilic droplets and were arranged in nests and cords in the eosinophilic matrix. Both the intracytoplasmic droplets and the matrix were stained positively with PAS. The visceral cells were cylindriform, and proliferated in papillary and tubular patterns and occasionally formed Shiller-Duval body-like structures. In the dissemination sites, the neoplastic cells proliferated on the surface of the various tissues and often infiltrated into deeper parts of the tissues. Immunohistochemically, both neoplastic cells were positive for α-fetoprotein and keratin, and the eosinophilic matrix was positive for laminin. Ultrastructurally, the parietal cells had dilated rough endoplasmic reticulums, which were filled with electron-lucent laminated structures. The visceral cells had poorly to moderately developed intracytoplasmic organelles and were interconnected with desmosomes. Taken together, the present tumor was diagnosed as yolk sac carcinoma arising from the ovary and was characterized by not only high metastasis but also invasive infiltration with biphasic proliferation of the parietal and visceral cells.

A case report of a metastatic yolk sac carcinoma in the pulmonary artery of a young female Sprague-Dawley rat

“…3B, 3C, 3D), respectively. All of the morphological, histochemical, and immunohistochemical findings were highly comparable to the previously reported cases of yolk sac carcinoma in rodents 2 , 4 , 5 , 10 . PTAH staining was performed to differentiate the possibility of thrombi and produced a negative result.…”

“…In the present case, a visceral pattern was not obvious, and the majority of the components showed a parietal pattern; however, the results of PAS reaction and immunohistochemistry for laminin strongly supported the diagnosis of this tumor as a yolk sac carcinoma. Cytokeratin has also been reported to be positive in rat yolk sac carcinoma cells 4 . Increased levels of AFP were detected in the sera of rats or humans bearing yolk sac carcinomas.…”

“…The incidence of yolk sac carcinoma in rats is extremely low, with only 1 case occurring in more than 40,000 female F344 rats used in previous carcinogenicity studies 1 . There have been some other reports of yolk sac carcinomas that developed in the ovary or uterus in aged female rats 2 , 3 , 4 . Nakazawa and colleagues reported an instance of testicular yolk sac carcinoma in an aged Sprague-Dawley (SD) rat 5 .…”

Diagnostic Exercise

“…By immunohistochemistry, visceral cells are positive for a-fetoprotein (AFP), although AFP reaction has also been reported in parietal cells. 3,9,12 Tumor cells are also positive for keratin, while PAS-positive material is positive for laminin. 6,9 In humans, the most specific markers for yolk sac tumors are AFP and glypican 3.…”

Spontaneous Nonmetastatic Choriocarcinoma, Yolk Sac Carcinoma, Embryonal Carcinoma, and Teratoma in the Testes of a Swiss Albino Mouse

“…Testicular yolk sac carcinoma has been reported in the SD rat (Nakazawa et al 1998) and in a Japanese black calf (Kagawa et al 1998). Recently, a case of highly metastatic ovarian yolk sac carcinoma in a Crl:CD (SD) rat has been reported (Sakamoto et al 2011). Ovarian choriocarcinoma occurring with yolk sac carcinoma and teratoma has been reported in B6C3F1 mice (Frith and Evans 1993).…”