This is a cancer or malignant growth that begins in an ovary. It is usually undetected until it is large enough to cause symptoms in the advanced stage as such it is a leading cause of morbidity. There are three (3) main types of ovarian cancer
depending on the cell in which it develops. 
Epithelial Tumor: it is the most common type of ovarian cancer and it starts from the cell that covers the outer surface of the ovary.
Germ Cell Tumor: This cancer cells starts from the cells that produce eggs  cell (ova).
Stromal Tumor: This tumor starts from the structural tissue that holds the ovary together and produce the female hormones oestrogen and progesterone.
            The major cause of ovarian cancer is unknown but about 10% is associated with a family history of breast, endometrial colon or ovarian cancer.
The use of hormonal drugs, drugs, high fat diet, smoking, alcohol use and environmental pollutions can predispose one to ovaries cancer. It is more incidence in women over 50 years of age.
CLINICAL MANIFESTATION
The early stage of the disease is asymptomatic (having no symptoms). The first manifestations are usually vague. There is abdominal discomfort, indigestion flatulence, anorexia, pelvic pressure, weight gain or loss etc.
The late manifestations may include severe abdominal pain which may be secondary to torsion of the ovarian mass backaches, bloating, trouble eating or feeling full quickly etc.
DIAGNOSTIC EVALUATIONS
Pelvic examination to detect enlargement, modularity immobility of ovaries.
Transvaginal ultrasound (TVUS): Here, sound waves are used to look at the uterus, fallopian tubes and ovaries by putting ultrasound wand into the vagina which can help find tumor in ovary.      
Tumor marker cancer antigen CA-125 blood test: CA 125 is a protein in the blood. In many women with ovaries cancer, the level of CA-125 is high. The high level usually goes down it treatment is working.
Pelvic sonography (trans-abdominal and trans-virginal) and CT scan: ovarian masses greater than 8-10cm are suspicious of malignancy.
MEDICAL MANAGEMENT
Surgery Omentectomy and Oophorectomy: This is the usual treatment. It also entails removal of one or both ovaries this is so because diagnosis is usually delayed. Optimal debunking to less than 1cm is the goal. 
Chemotherapy: This is most effective if tumor is optically debunked. This may be given intravenously (iv) or intraperitoneal. It is indented to prevent a diseased reoccurrence.
Radiation therapy; although not usually valuable but may be used to prevent local reoccurrence.
Hormonal Therapy:- This is usually achieved by the use of taxmoxifen. (tamofen) an antioestrogen agent. Progestin may be used depending on oestrogen receptor/progesteron receptor status.