The metabolism of neoplastic cells is perceived as the cause of atherothrombotic incidents in cancers since the 19th century. Those incidents occur in 1–11% cancer cases. In clear cell carcinoma, accounting for 5% of ovarian cancers, atherothrombotic incidents tend to occur 2.5 times more frequently. Clear cell carcinoma is diagnosed earlier and at a younger age compared to other ovarian cancers. The cancer is also characterized by drug resistance to standard treatment. A 47-year-old patient was admitted to the Department of Gynaecology and Obstetrics of School of Medicine in Katowice to treat a tumor of the right ovary. The tumor was detected a month before during the diagnostics of an ischemic stroke which occurred despite no risk factors being present. A laparotomy was performed and the tumor, left adnexa and uterus were removed, according to ovarian cancer protocol. Histopathological examination confirmed the diagnosis of adenocarcinoma clarocellulare (clear cell carcinoma – CCC). The patient was referred for further oncological treatment on 5th day after surgery. Oncological alertness needs to be maintained in cases of unexplained atherothrombotic incidents. An interdisciplinary approach can improve patients’ prognosis by diagnosing the cancer earlier.