Positive immunohistochemical staining of CD117 is a typical marker of OD.[8] OD is a moderate and low-grade malignant tumor, and the prognosis is generally satisfactory after surgery and adjuvant chemotherapy or radiotherapy.[9] The patient presented here showed a large solid pelvic mass, significant serum CA125 elevation, and positive immunohistochemical staining of CD117, which is consistent with the diagnosis of OD. This evidence concerns the gene KIT and cancer.