Figure 4
Representative hematoxylin and eosin stained sections of the varied germ cell components that may be seen in a polyembryoma (Case 2). Mature (not pictured) and immature teratomatous elements (a, bottom left) may be present. The yolk-sac epithelium, which comprises a portion of the embryoid body, may proliferate into larger aggregates, forming a yolk-sac tumor component (a, bottom right b, left). The embryoid bodies may fuse to form an expansile aggregate (c). Additional germ cell components, such as embryonal carcinoma (d), may also be present.
