Diagnosis: Yolk sac tumor.

Comment: Multiple sections from this tumor showed only yolk sac tumor. When occurs in a prepubertal child, yolk sac tumor is almost always a pure neoplasm, whereas in postpubertal patients it is one component of a mixed germ cell tumor and very rarely pure. The tumor presents more than 10 different histologic patterns. The reticular pattern (Figs. 1 and 2) is the more common. The Schiller-Duval bodies (Fig. 4) are seen in approximately 75% of the cases. Vascular invasion present in this particular tumor (Fig. 5) must be reported because corresponds to stage pT2.