Endometriosis is a common clinical disorder in premenopausal women. Although endometriosis is a benign gynecologic disorder, malignant ovarian tumors have been documented to arise in women with endometriosis. The pathogenesis by which endometriosis associated ovarian cancer develops remain poorly understood. Here we report a case of EAOC, and discuss the potential pathogenesis, clinicopathologic features and clinical regime.