Embryonal carcinoma of an ovary. Light micrograph showing primitive, high-grade tumour cells forming anastomosing cords and trabeculae. They are separated by moderate amount of pink stroma. Primary embryonal carcinoma (EC) of the ovary is an exceedingly rare tumour and is seen less frequently in the ovary than in the testis. It comprises about 3% of malignant ovarian germ cell tumours. Pure EC is rare and is more likely to occur in children and adolescent patients, whereas in adults it occurs as a component of mixed germ cell tumour. Haematoxylin and eosin stained section. Magnification: x200 when printed at 10 centimetres wide.