Coexistence of endometriosis and ovarian germ cell tumors

Introduction: Endometriosis, like ovarian germ cell tumors with the most frequent finding being dermoid cysts, are two entities characterized by the presence of well-differentiated cells in an ectopic location and they mostly appear in women of reproductive age. The purpose of our study is to evaluate the coexistence of these two entities, summarize the clinical characteristics of women diagnosed with both entities, and monitor symptoms after diagnosis and treatment. Materials and Methods: This is a retrospective study involving patients from the Cantonal Hospital of Schaffhausen and the Second University Department in Obstetrics and Gynecology, Hippokration General Hospital of Thessaloniki, who underwent surgery between 2011 and 2019. Histological diagnosis of endometriosis or ovarian germ cell tumors was a prerequisite for inclusion in the study. A follow-up questionnaire was mailed to all patients included in this study who had both endometriosis and ovarian germ cell tumors. The primary outcome of this study is the coexistence of endometriosis with ovarian germ cell tumors, and the secondary outcomes are the data from the postoperative follow-up of these patients. The paired t-test was used for comparing numerical variables, and the chi-square test was used for comparing categorical variables. A p-value of less than 0.05 was considered statistically significant. Results: In this study, we found that 26.5% of patients with mature cystic teratomas also have endometriosis. Follow-up of these patients showed a significant reduction in dysmenorrhea, and 5 out of 11 women with a desire for future pregnancy had at least one pregnancy postoperatively. The correlation of endometriosis with other ovarian germ cell tumors varies from 0% (carcinoid, yolk sac tumors, immature teratomas) to 100% (polyembryoma). However, ovarian germ cell tumors other than teratomas are extremely rare, indicating the difficulty of correlating them with endometriosis. None of the malignant ovarian germ cell showed reccurence during the follow-up period. Conclusions: Gynecologists should be aware of this correlation and preoperatively advise women appropriately regarding fertility preservation techniques, as this population has an increased risk of reduced ovarian reserves postoperatively.