Mature Ovarian Teratoma in a Cynomolgus Monkey (Macaca fascicularis)

An ovarian tumor was observed in a five-year-old, female cynomolgus monkey. The tumor occupied the entire left ovary, and normal ovarian tissue was not observed. The tumor was composed of endodermal, mesodermal and ectodermal cell components with well-differentiated tooth and bone formation. The present tumor was diagnosed as a mature ovarian teratoma.