RESUMO
@#Primary ovarian leiomyosarcoma is a very rare tumor which is most commonly seen in postmenopausal women. Primary ovarian leiomyosarcoma has a very poor prognosis, with less than 20% of patients being alive at 5 years. The case is a 51‑year‑old female who presented with a lower abdominal mass secondary to an ovarian new growth. An exploratory laparotomy, peritoneal fluid cytology, unilateral salpingo‑oophorectomy with malignant frozen section of affected ovary, which revealed malignant tumor, proceeded with surgical staging total abdominal hysterectomy contralateral salpingo‑oophorectomy, then proceeded to complete surgical staging with infracolic omentectomy, Jackson‑Pratt drain insertion was performed. Microscopic and immunohistochemical findings established the diagnosis of primary ovarian leiomyosarcoma. Surgery is the cornerstone of treatment, while the role of chemotherapy and radiotherapy is still not clear because substantial data are lacking. The prognosis of primary pure ovarian leiomyosarcomas is extremely poor and there is no established treatment modality for this rare type of tumor.