Despite the dynamic advances in medicine, ovarian tumors still remain a serious diagnostic and therapeutic issue. There is an ongoing search for an ideal method of early detection of ovarian malignancy. Although malignant lesions are most common in adult women, they may also occur in teenage girls (e.g. germ cell tumors). It is estimated that gonadal tumors account for about 7% of ovarian malignancies, therefore they are considered rare. Tumors belonging to this specific group develop both from female and male gonad components as well as from stromal cells and fibroblasts. Granulosa cell tumors account for as much as 70% of malignant gonadal tumors: 95% in the mature form and 5% in the juvenile form. Gonadal tumors further include thecomas and fibromas, Sertoli–Leydig cell tumors as well as very rare tumors, such as gynandroblastoma, sex cord tumors with annular tubules and sclerosing stromal tumors. The histological structure of sclerosing stromal tumors shows male and female gonadal endocrine cells. For this reason, these tumors often show hormonal activity, as reflected in the clinical course of the disease. Sclerosing stromal tumor of the ovary is an extremely rare cancer belonging to the theca cell-fibrous group. The paper presents macro- and microscopic characteristics, diagnostics, symptomatology and therapeutic methods in sclerosing stromal tumor patients. The importance of early ovarian malignancy detection was emphasized.