The coexistence of endometrioma with dermoid cyst of the ovaries is an unusual entity, although they are both common and benign gynecological tumors. The present study aimed to investigate the association between ovarian dermoid cyst (teratoma) and endometrioma. We retrospectively, included 315 women with endometrioma and 172 with ovarian teratoma. Data were collected from medical and pathological reports from two different areas between 1995 and 2018. The mean age of cases with endometrioma was similar (35.8±7.2 years) to patients with ovarian teratoma (34.2±6.8 years). Considering the types of dermoid cysts, the observed proportion of mature type was 168/172 (98%), the immature type was 4/172 (2%) and struma ovarii was14/172 (8.1%) respectively. Endometrioma was significantly more frequent in the left ovary [174/266 (65.4%)] than in the right ovary [92/266 (34.6%)], P<0.001. By contrast, ovarian teratoma were predominant in the right ovary, 98/172 (60.6%), compared to the left side, 56/172 (32.5%), P<0.001. Regarding the size of the masses, we detected an inverse distribution between the two groups. Thirteen women were detected with ovarian teratoma and endometriosis, with 6 cases being in the same ovary. Our results indicate a left lateral predispostion of endometrioma and a right of ovarian teratoma and suggest that the pathogenesis between these conditions is different. The coexistence of endometriosis with dermoid cyst of the ovary, presents a challenge to the physicians and the investigators. Further research is required to establish the relationship between endometriosis and ovarian teratoma.
Keywords: endometrioma; endometriosis; ovarian teratoma.