Familial occurrence of mature ovarian teratomas.

It has been suggested that genetic predisposing factors play a role in the development of ovarian teratomas. Familial occurrence of these tumors would support this view. Reported herein are identical twins, both of whom had a right ovarian mature teratoma. In both cases the presenting symptoms were acute torsion. The diagnosis was confirmed at laparotomy and subsequent histopathologic examination. The origin of ovarian teratomas seems to be linked to the process of parthenogenesis. This process probably involves a germ cell after its first meiotic division.