Germ Cell Tumors of the Ovary

Abstract

This group of ovarian neoplasms is composed of a number of histologically different tumor types and embraces all the neoplasms considered to be ultimately derived from the primitive germ cells of the embryonic gonad. The concept of germ cell tumors as a specific group of gonadal neoplasms has evolved in the last three decades and has become generally accepted. This concept is based primarily on the common histogenesis of these neoplasms, on the relatively frequent presence of histologically different tumor elements within the same tumor mass, on the presence of histologically similar neoplasms in extra-gonadal locations along the line of migration of the primitive germ cells from the wall of the yolk sac to the gonadal ridge,²⁴⁴ and on the remarkable homology between the various tumor types in the male and the female. In no other group of gonadal neoplasms is this homology better illustrated. Although the strong morphologic resemblance between the testicular seminoma and its ovarian counterpart the dysgerminoma was noted soon after these neoplasms were first described, for a long time there was no agreement as to their histogenesis. Nevertheless, these were the first neoplasms to become accepted as originating from germ cells. However, it was not until the studies by Teilum^212,213 on the homology of ovarian and testicular neoplasms, the studies by Friedman and Moore⁶⁶ and Dixon and Moore,⁵² on testicular tumors, and those by Friedman⁶⁵ on related extragonadal neoplasms that the germ cell origin of other neoplasms belonging to this group was suggested. These views were supported by the embryologic studies by Witschi²⁴⁴ and Gillman,⁷⁰ and later by the experimental work of Stevens^198–200 and Pierce and his collaborators156 ^158,161,162 on germ cell tumors in rodents. The histogenesis and the interrelationship of the various types of germ cell neoplasms as has been suggested by Teilum²¹⁷ is shown in Figure 26.1.