Endometriosis is a prevalent inflammatory gynecologic disease in women of reproductive age that affects up to 15% of the women. It has been reported that majority of the malignant tumors are associated with endometriosis along with clear cell and invasive endometrioid ovarian malignancy. However, in this case presentation, we have identified an association of endometriosis and sex cord tumor with annular tubules. It was considered as a disease with some conditions which make it appear not malignant for sharing some properties related to cancer and some other malignant tumors are associated with the endometriotic type and clear cell ovarian cancer. However, in this case report, we have identified coincidence of endometriosis and sex cord tumor with annular tubules. The ultimate goal of this study was to draw the attention of the readers to the point that endometrioma could be accompanied not only by clear cell and endometrioid ovarian cancer but also by other ovarian cancers. This case was considered in the study to conduct further research if similar cases are observed.