Mixed Germ Cell Tumor : Polyembryoma
Embryoid bodies in a polyembryoma pattern of mixed germ cell tumor. The embryoid bodies consist of a central semicircular plate of cuboidal or columnar embryonal carcinoma cells, a dorsal space lined by flattened epithelium (reminiscent of amniotic sac), and a ventral yolk sac tumor component with reticular and myxomatous architecture. The embryoid bodies are surrounded by loose vascular tissue resembling extraembryonic mesenchyme. All features may or may not be seen depending upon the plane of the section through the embryoid body.