Germ Cell Tumors of the Ovary

Abstract

Germ cell tumors are composed of a number of histologically different tumor types 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 over the last several decades. It is based on (1) the common histogenesis of these neoplasms, (2) the relatively frequent presence of histologically different neoplastic elements within the same tumor, (3) the presence of histologically similar neoplasms in extragonadal locations along the line of migration of the primitive germ cells from the wall of the yolk sac to the gonadal ridge (Witschi, Contrib Embryol 32:67, 1948), and (4) the remarkable homology between the various tumors in males and females. 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. It was not until the studies by Teilum (Acta Obstet Gynecol Scand 24:480, 1944; Acta Pathol Microbiol Scand 23:242, 1946) on the homology of ovarian and testicular neoplasms, the studies by Friedman and Moore (Mil Surg 99:573–593, 1946) and Dixon and Moore (Tumors of the male sex organs. Atlas of tumor pathology, sect VIII, fasc 31b, 32. Armed Forces Institute of Pathology, Washington, DC, 1952) on testicular tumors, and those by Friedman (Cancer (Phila) 4:265–276, 1951) on related extragonadal neoplasms that the germ cell origin of other neoplasms belonging to this group was proposed. These views were supported by the embryologic studies of Witschi (Contrib Embryol 32:67, 1948) and Gillman (Contrib Embryol 32:83, 1948) and later by the experimental work of Stevens (J Natl Cancer Inst 23:1249–1295, 1959; Dev Biol 2:285–297, 1960; Annee Biol 1:585–610, 1962) and Pierce et al. (Am J Pathol 41:549–566, 1962; Pierce and Verney, Cancer (Phila) 14:1017–1029, 1961) on germ cell tumors in rodents.

Although occasional unusual neoplasms composed of germ cells and sex cord derivatives had been noted previously, it was not until Scully’s detailed description of gonadoblastoma (Scully, Cancer (Phila) 6:455–463, 1953) that these neoplasms were established as a distinct entity. More recently, another neoplasm composed of germ cells and sex cord derivatives, the mixed germ cell–sex cord–stromal tumor, has been described in detail (Talerman, Cancer (Phila) 30:1219–1224, 1972a; Talerman, Obstet Gynecol 40:473–478, 1972b). This chapter, therefore, is devoted not only to neoplasms of germ cell origin but also to those composed of germ cells and sex cord derivatives.